HIRA (Hazard Identification and Risk Assessment) :

 HIRA (Hazard Identification and Risk Assessment) :

The purpose of this guideline is to provide a systematic and objective approach to assessing

hazards and their associated risks that will provide an objective measure of an identified hazard as well as provide a method to control the risk. It is one of the general duties as prescribed under the Occupational Safety and Health Act 1994 (Act 514) for the employer to provide a safe workplaces to their employees and other related person.

Term And Definitions:

Hazard means a source or a situation with a potential for harm in terms of human injury or ill health, damage to property, damage to the environment or a combination of these.

Hazard control means the process of implementing measures to reduce the risk associate with a hazard.

Hierarchy of control means the established priority order for the types of measures to be used to control risks.

Hazard identification means the identification of undesired events that lead to the materialization of the hazard and the mechanism by which those undesired events could occur.

Risk means a combination of the likelihood of an occurrence of a hazardous event with specified period or in specified circumstances and the severity of injury or damage to the health of people, property, environment or any combination of these caused by the event.

Risk assessment means the process of evaluating the risks to safety and health arising from hazards at work.

Risk management means the total procedure associated with identifying a hazard, assessing the risk, putting in place control measures, and reviewing the outcomes.

Basic Concepts:

What is risk?

Risk is something that we as individuals live with on a day-to-day basis. People are constantly making decisions based on risk. Simple decision in daily life such as driving, crossing the road and money investment all imply an acceptance risk. Risk is the combination of the likelihood and severity of a specified hazardous event occurring.

In mathematical term, risk can be calculated by the equation - Risk = Likelihood x Severity

Where,

Likelihood is an event likely to occur within the specific period or in specified circumstances

and,

Severity is outcome from an event such as severity of injury or health of people, or damage to property, or insult to environment, or any combination of those caused by the event.

Planning And Conducting Of Hira :

The purpose of HIRA are as follows:-

a. to identify all the factors that may cause harm to employees and others (the hazards);

b. to consider what the chances are of that harm actually be falling anyone in the circumstances of a particular case and the possible severity that could come from it (the risks); and

c. to enable employers to plan, introduce and monitor preventive measures to ensure

that the risks are adequately controlled at all times.

HIRA activities shall be plan and conducted :

a) for situation :

     i. where hazard appear to pose significant threat;

     ii. uncertain whether existing controls are adequate; or/and

     iii. before implementing corrective or preventive measures.

b) by organization intending to continuously improve OSH Management System. It should be the duty of the employer to assign a trained personnel to lead a team of employees associated with one particular process or activity to conduct HIRA.

Process of HIRA

Process of HIRA requires 4 simple steps :

(a) classify work activities;

(b) identify hazard;

(c) conduct risk assessment (analyze and estimate risk from each hazard), by calculating or estimating -

      i. likelihood of occurrence, and

      ii. severity of hazard;

(d) decide if risk is tolerable and apply control measures (if necessary).

Flow chart for HIRA process

Classify work activities →Consultation ( between Employer and Employees)→Identify Hazards → Risk Assessment → Prepare Risk Control Action Plan ( if necessary) → Implement →(review /loop back to Identify Hazards). 

Classify work activities:

Classify work activities in accordance with their similarity, such as :

1. geographical or physical areas within/outside premises;

2. stages in production/service process;

3. not too big e.g. building a car;

4. not too small e.g. fixing a nut; or

5. defined task e.g. loading, packing, mixing, fixing the door.

Hazard identification:

The purpose of hazard identification is to highlight the critical operations of tasks, that is, those tasks posing significant risks to the health and safety of employees as well as highlighting those hazards pertaining to certain equipment due to energy sources, working conditions or activities performed. Hazards can be divided into three main groups, health hazards, safety hazards, and environmental hazards.

Health hazards:

An occupational health hazard is any agent that can cause illness to an individual. A health hazard may produce serious and immediate (acute) affects, or may cause long-term(chronic) problems. All or part of the body may be affected. Someone with an occupational illness may not recognize the symptoms immediately. For example, noise-induced hearing loss is often difficult for the affected individual to detect until it is well advanced. Health hazards include chemicals (such as battery acid and solvents), biological hazards (such as bacteria, viruses, dusts and molds), physical agents (energy sources strong enough to harmthe body, such as electric currents, heat, light, vibration, noise and radiation) and work design (ergonomic) hazards.

Safety hazards:

A safety hazard is any force strong enough to cause injury, or damage to property. An injury caused by a safety hazard is usually obvious. For example, a worker may be badly cut. Safety hazards cause harm when workplace controls are not adequate.

Some examples of safety hazards include, but are not limited to:

• slipping/tripping hazards (such as wires run across floors);

• fire hazards (from flammable materials);

• moving parts of machinery, tools and equipment (such as pinch and nip points);

• work at height (such as work done on scaffolds);

• ejection of material (such as from molding);

• pressure systems (such as steam boilers and pipes);

• vehicles (such as forklifts and trucks);

• lifting and other manual handling operations; and

• working alone.

Environmental hazards:

An environmental hazard is a release to the environment that may cause harm or deleterious effects. An environmental release may not be obvious. For example, a worker who drains a glycol system and releases the liquid to a storm sewer may not be aware, of the effect on the environment. Environmental hazards cause harm when controls and work procedures are not followed.

Hazard identification technique:

The employer shall develop a hazard identification and assessment methodology taking into account the following documents and information :

• any hazardous occurrence investigation reports;

• first aid records and minor injury records;

• work place health protection programs;

• any results of work place inspections;

• any employee complaints and comments;

• any government or employer reports, studies and tests concerning the health and safety of employees;

• any reports made under the regulation of Occupational Safety and Health Act, 1994

the record of hazardous substances; and

• any other relevant information.

The hazard identification and assessment methodology:

The hazard identification and assessment methodology shall include:

a. Steps and time frame for identifying and assessing the hazards. One must define the steps for the identification of hazards and a time frame for this identification. The following information should be included :

            i) who will be responsible for the identification: for example, it may be the work place health and safety committee, or an individual or individuals appointed.by the committee;

           ii) the way in which the identification reports are processed: for example, they may be compiled and processed by the committee, or by individuals appointed by the committee:                      

          iii) the identification time frame: for example, the identification of hazards for

              workshop A must be completed in December, for workshop B in April and for workshop C in November.

b. The keeping of a record of the hazards.

           After having identified the hazards, one must establish and maintain an identification record, either in print or electronic format.

c. A time frame for reviewing and, if necessary, revising the methodology.

The date for the review of the identification: for example, the review of the identification method will be carried out every three years.

To complete hazard identification, one can use techniques to identify hazards. Some examples of techniques include, but are not limited to:

         i. work place inspections;

         ii. task safety analysis or job hazard analysis;

         iii. preliminary investigations;

         iv. potential accident factors;

         v. failure analysis;

         vi. accident and incident investigations.

It is in your interest to adopt your own process and your own identification techniques so that they match one management procedures and the size of business. In fact, the identification method may vary depending on the size of the work place.

Analyze and estimate risk:

Risk is the determination of likelihood and severity of the credible accident/event sequences in order to determine magnitude and to priorities identified hazards. It can be done by qualitative, quantitative or semi quantitative method.

A qualitative analysis uses words to describe the magnitude of potential severity and the likelihood that those severity will occur. These scales can be adapted or adjusted to suit the circumstances and different descriptions may be used for different risks. This method uses expert knowledge and experience to determine likelihood and severity category.

In semi-quantitative analysis, qualitative scales such as those described above are given values. The objective is to produce a more expanded ranking scale than is usually achieve in qualitative analysis, not to suggest realistic values for risk such as is attempted in quantitative analysis.

Quantitative analysis uses numerical values (rather than the descriptive scales used in qualitative and semi-quantitative analysis) for both severity and likelihood using data from a variety of sources such as past accident experience and from scientific research. Severity may be determined by modeling the outcomes of an event or set of events, or by extrapolation from experimental studies or past data. Severity may be expressed in terms of monetary, technical or human impact criteria, or any of the other criteria. The way in which severity and likelihood are expressed and the ways in which they are combined to provide a level of risk will vary according to the type of risk and the purpose for which the risk assessment output is to be used.

In this guidelines qualitative and semi quantitative method uses as an example.

Likelihood of an occurrence:

This value is based on the likelihood of an event occurring. You may ask the question “How many times has this event happened in the past?” Assessing likelihood is based worker experience, analysis or measurement. Likelihood levels range from “most likely” to “inconceivable.” For example, a small spill of bleach from a container when filling a spray bottle is most likely to occur during every shift. Alternatively, a leak of diesel fuel from a secure holding tank may be less probable.

Table A indicates likelihood using the following values:

Table A indicates likelihood using the following values:

Severity of hazard:

Severity can be divided into five categories.

Severity are based upon an increasing level of severity to an individual’s health, the environment, or to property. Table B indicates severity by using the following table : 

( Table B )

SEVERITY (S): Catastrophic, 

EXAMPLE (E): Numerous fatalies, irrecoverable property damage and productivity, 

RATING (R): 5.

SEVERITY (S): Fatal

EXAMPLE (E): Approximately one single fatality, major property damage if  hazard is realized

RATING (R): 4

SEVERITY (S): Serious

EXAMPLE (E): Non-fatal injury, permanent disability

RATING (R): 3

SEVERITY (S): Minor 

EXAMPLE (E): Disabling but not permanent injury

RATING (R): 2

SEVERITY (S): Negligible  

EXAMPLE (E):   Minor abrasions, bruises, cuts,  first aid type injury

RATING (R): 1

Risk assessment :

Risk can be presented in variety of ways to communicate the results of analysis to make decision on risk control. For risk analysis that uses likelihood and severity in qualitative method, presenting result in a risk matrix is a very effective way of communicating the distribution of the risk throughout a plant and area in a workplace.

Risk can be calculated using the following formula:

L x S = Relative Risk

L = Likelihood

S = Severity

An example of risk matrix (Table C) is shown below:

To use this matrix, first find the severity column that best describes the outcome of risk.Then follow the likelihood row to find the description that best suits the likelihood that the severity will occur. The risk level is given in the box where the row and column meet.

The relative risk value can be used to prioritize necessary actions to effectively manage work place hazards. Table D determines priority based on the following ranges:

Hazards assessed, as “High Risk” must have immediate actions, to resolve risk to life safety and or the environment. Individuals responsible for required action, including follow up must be clearly identified. A further detail risk assessment method may require such as quantitative risk assessment as means of determine suitable controls measures.

Control:

Definition: Control is the elimination or inactivation of a hazard in a manner such that the hazard does not pose a risk to workers who have to enter into an area or work on equipment in the course of scheduled work.

Hazards should be controlled at their source (where the problem is created). The closer a control to the source of the hazard is the better. This method is often referred to as applying engineering controls. If this does not work, hazards can often be controlled along the path to the worker, between the source and the worker. This method can be referred to as applying administrative controls. If this is not possible, hazards must be controlled at the level of the worker through the use of personal protective equipment (PPE), although this is the least desirable control.

Selecting a suitable control:

Selecting a control often involves:

     a. evaluating and selecting short and long term controls;

     b. implementing short-term measures to protect workers until permanent controls can be put in place; and

     c. implementing long term controls when reasonably practicable.

For example, suppose a noise hazard is identified. Short-term controls might require workers to use hearing protection. Long term, permanent controls might remove or isolate the noise source.

Types of Control:

At the source of the hazard

    a. Elimination - Getting rid of a hazardous job, tool, process, machine or substance is perhaps the best way of protecting workers. For example, a salvage firm might decide to stop buying and cutting up scrapped bulk fuel tanks due to explosion hazards.

   b.Substitution - Sometimes doing the same work in a less hazardous way is possible.For example, a hazardous chemical can be replaced with a less hazardous one.Controls must protect workers from any new hazards that are created.

Engineering control:

a. Redesign - Jobs and processes can be reworked to make them safer. For example,containers can be made easier to hold and lift.

b. Isolation - If a hazard cannot be eliminated or replaced, it can some times be isolated, contained or otherwise kept away from workers. For example, an insulated and air-conditioned control room can protect operators from a toxic chemical.

c. Automation - Dangerous processes can be automated or mechanized. For example, computer- controlled robots can handle spot welding operations in car plants. Care must be taken to protect workers from robotic hazards.

d. Barriers - A hazard can be blocked before it reaches workers. For example, special curtains can prevent eye injuries from welding arc radiation. Proper equipment guarding will protect workers from con tacting moving parts.

e. Absorption - Baffles can block or absorb noise. Lockout systems can isolate energy sources during repair and maintenance. Usually, the further a control keeps a hazard away from workers, the more effective it is.

f. Dilution - Some hazards can be diluted or dissipated. For example,ventilation systems can dilute toxic gasses before they reach operators.

Administrative controls:

a. Safe work procedures - Workers can be required to use standardized safety practices. The employer is expected to ensure that workers follow these practices. Work procedures must be periodically reviewed with workers and updated.

b. Supervision and training – Initial training on safe work procedures and refresher training should be offered. Appropriate supervision to assist workers in identifying possible hazards and evaluating work procedures.

c. Job rotations and other procedures can reduce the time that workers are exposed to a hazard. For example, workers can be rotated through jobs requiring repetitive tendon and muscle movements to prevent cumulative trauma injuries. Noisy processes can be scheduled when no one is in the workplace.

d. Housekeeping, repair and maintenance programs - Housekeeping includes cleaning, waste disposal and spill cleanup. Tools, equipment and machinery are less likely to cause injury if they are kept clean and well maintained.

e. Hygiene - Hygiene practices can reduce the risk of toxic materials being absorbed by workers or carried home to their families. Street clothing should be kept in separate lockers to avoid being contaminated by work clothing. Eating areas must be segregated from toxic hazards. Eating should be forbidden in toxic work areas. Where applicable, workers should be required to shower and change clothes at the end of the shift.

Personal protective equipment:

Personal protective equipment (PPE) and clothing is used when other controls measures are not feasible and where additional protection is needed. Workers must be trained to use and maintain equipment properly. The employer and workers must understand the limitations of the personal protective equipment. The employer is expected to require workers to use their equipment whenever it is needed. Care must be taken to ensure that equipment is working properly. Otherwise, PPE may endanger a workers health by providing an illusion of protection.

Monitoring controls:

The effectiveness of controls must be checked regularly. Evaluate and monitor hazard controls during inspections, routine maintenance, and other activities.

Ask the following questions –

a. have the controls solved the problem?

b. is any risk to workers posed by the controls contained?

c. are all new hazards being identified?

d. are significant, new hazards appropriately controlled?

e. are accident reports being analyzed?

f. are any other measures required?

Document control activities to track their effectiveness, if necessary re-evaluate hazards and implement new control measures.

Safe work procedures:

Through the completion of a Job Hazard Analysis, sometimes hazards are identified and cannot be eliminated or engineered out of a particular task. Safe Work Procedures are step by step instructions that allow workers to conduct their work safety when hazards are present. A Safe Work Procedure identifies the materials and equipment needed, and how and when to use them safety.

Safe Work Procedures are generally prepared for -

a. critical high risk jobs where accidents have or could result in severe injuries;

b. hazardous work where accidents occur frequently;

c. new or altered tasks have been introduced;

d. new equipment has been added to a process;

e. a job that requires many detailed tasks;f. where two or more workers required for a job, and each must perform specific

tasks simultaneously; and

g. specific tasks are done infrequently.

Safe Work Procedures must include:

a. regulatory requirements;

b. necessary personal protective equipment;

c. required training;

d. worker responsibilities;

e. specific sequence of steps to follow to complete the work safely;

f. required permits; and

g. emergency procedures.

An example of a task that requires the development of a safe work procedure is confined space entry. Individuals who must work within confined spaces must ensure that safe work procedures are developed and followed to maximize life safety.

Personal protective equipment (PPE):

Personal protective equipment means any equipment which is intended to be worn or held by a person at work and which protects him against one or more risks to his health or safety and any additional accessory designed to meet that objective;

PPE is usually chosen to provide protection appropriate to each of type of hazard present. There are specifications for the types of PPE used for protecting an individual’s head, eyes, footwear, limb and body, fire retardant clothing, respiratory, hearing, and personal flotation devices.

It may also include required apparel for example when traffic hazards are present high

visible and distinguishable “vests must be worn”

Documenting HIRA:

Responsibility and accountability

Proper management of hazards sporadically identified in the workplace can be done through effective process. Ultimately, the individual or team who identified the hazard must ensure proper communication of the hazard to the appropriate workplace authority (manager, department head, or designated person). Each HIRA must be fully documented. The HIRA form must be completed by the HIRA team and signed by the in charge personnel of the area. Departments responsible for the hazards and their control are required to maintain all records of assessments for at least 3 years. (In some cases, legislative requirements will determine the minimum time to retain records).

The appropriate authority is responsible for ensuring that effective and timely controls are applied to the hazard and communicating the results back to the originator. Management or employer must endorse and approve the HIRA results. Employer must communicate all HIRA to employees, monitor the follow up action and keep the records. The HIRA Form (Link below the page, click here) is an example to document the HIRA process.

Documenting process:

Instructions to team leader and persons conducting HIRA :

1. complete HIRARC Form. It is recommended to use a single form for each work process;

2. record the names and designation of HIRAC team members;

3. outline the process workflow and indicate in the form under ‘process/ location column;

4. list all activities ( routine and non-routine) for each work process under the “Work Activity” column;

5. identify the hazards associated with each activity and record in “Hazard” column;

6. determine the effect of each hazard identified and record in “Effect” column;

7. record any existing hazard control measures;

8. determine likelihood (L) from Table A and severity (S) from Table B for eachhazard. Assign P and C rating in respectively column. The existing control measures should be take into consideration while determine (L) and (S);

9. by using Risk Matrix ( Table C and D ) assign one risk and record in “Risk” column;

10. based on the risk assigned, recommend appropriate risk control measures ( see Table D);

11. assign a suitable person to implement the recommended risk control and indicate the follow up action date and status;

12. repeat the HIRA for other activities and process;

13. conduct another round of HIRA after control measures have been implemented; 

and

14. review HIRA for every three years or whenever there are changes in process or

APPENDIX A

Examples of Workplace Hazards:

The Hazard Identification listed is to assist in the identification of hazards in the work place. This table provides some additional explanation of the meaning of the hazard classifications.

WORK ENVIRONMENT

Adequate Access : Refers to adequate access to, from and within the workplace.

Air Conditioning: Refers to the uncontaminated air in the work space.

Confined Space: Means enclosed work spaces where people normally do not work (defined in standards)

Temperature Extremes: a) Heat, This includes contact with hot objects, hyperthermia,  fire (Non explosions)

b) Cold, This includes contact with cold objects and hypothermia

Lighting: Refers to adequate illumination for the particular work being done 

Mental Stress: Includes bullying, workplace violence, shift work, excessive work loads 

Dehydration: Adequate water supply for the individuals while working

ENERGY

 

Herd immunity

Following a vaccination, a person can become immune to the specific disease. This immunity gives protection against illness in an individual.

Vaccinating the majority of the population against serious diseases can reduce the chance of people coming into contact with specific pathogens. This leads to herd immunity.

There are three recognised scenarios in relation to herd immunity:

1. • Scenario 1: 
   • •The majority of the population are not vaccinated against a specific disease but are healthy.
   • •A few people are not vaccinated and ill and contagious.
   • •This can develop easily into a mass infection because the majority of the population are not vaccinated.
2. • Scenario 2: 
   • •The majority of the population are not vaccinated against the specific disease but are well.
   • •Some are vaccinated and healthy
   • •A few are not vaccinated and ill and contagious.
   • •Mass infection can result again, but a small number of vaccinated individuals remain healthy and some not vaccinated will also be healthy.
3. • Scenario 3: 
   • •The majority of the population are vaccinated against a specific disease and are healthy.
   • •A few are not vaccinated but well.
   • •A few are not vaccinated against the disease and they are ill and contagious.
   • •The result is that the majority are protected due to the high level of vaccination. A few individuals will still become ill, but the large number of vaccinated individuals gives protection.

Immunisation against disease

Data sourced from publichealthmatters.org (2015)Number of laboratory-confirmed cases of measles in Scotland, 1988-2019. Source: Health Protection Scotland.

How vaccination and herd immunity works

Why is it called “herd immunity,” do you think?

A recent article in the journal Lancet offers a fascinating history of the phrase and, as it turns out, it’s called “herd immunity” because it originated in reference to cows.

In the 1910s, a disease was spreading around U.S. cattle farms causing “epidemics of spontaneous miscarriage” (they called it “abortion disease”), and farmers were destroying cows as a way to solve the problem.

Enter veterinarian George Potter who, writing in the Journal of the American Veterinary Medical Association, apparently coined the phrase “herd immunity.”

“Abortion disease may be likened to a fire, which, if new fuel is not constantly added, soon dies down,” Potter wrote. “Herd immunity is developed, therefore, by retaining the immune cows, raising the calves, and avoiding the introduction of foreign cattle.”

A few years later, bacteriologist W.W.C. Topley did some experiments on mice and wrote about the results. When the mice stopped catching the introduced illness, Topley said they had gained “herd immunity.”

Topley thought the idea might also apply to children and in 1924, Sheldon Dudley, a professor of pathology at the Royal Naval Medical School, tested the concept at the Royal Hospital School in Greenwich, where there was a diphtheria outbreak.

“I will now consider the community, or the herd,” Dudley wrote in 1929. “Nations may be divided into urban or rural herds. Or we can contrast the shoregoing herd with the sailor herd, or herds dwelling in hospitals can be compared with those who live in mental hospitals.”

By the 1930s, the idea of herd immunity was considered as a way to handle influenza, polio, smallpox and typhoid, among other diseases, but thinking began to shift in the 1950s when vaccines became available.

Most recently, commentators in Lancet have argued that, considering the fact that COVID-19 antibodies might not actually provide protection from the virus, “any proposed approach to achieve herd immunity through natural infection is not only highly unethical, but also unachievable.”

History of herd immunity

Yes. As many countries around the world recognised the magnitude of the COVID-19 pandemic in March, 2020, some seemed to put their faith in herd immunity. UK pandemic adviser Graham Medley, for example, said that “We are going to have to generate what we call herd immunity”, which would require “a nice big epidemic”. When the idea received furious criticism, British officials denied that herd immunity had ever been part of their plan. A run at herd immunity in Sweden prompted mathematician Marcus Carlsson to object: “we are being herded like a flock of sheep toward disaster”. In August, WHO's Michael Ryan warned journalists “we are nowhere close to the levels of immunity required to stop this disease transmitting. We need to focus on what we can actually do now to suppress transmission and not live in hope of herd immunity being our salvation.” That did not end the debate. In late August sources revealed that the White House might be pondering a policy of herd immunity. Officials issued a prompt denial. The appeal of herd immunity is easy to understand: if it is reached, an epidemic ends. But the illness and death such an approach would require have prompted a strong backlash. The language of herd immunity is part of the problem. A herd usually describes domesticated animals, especially livestock. Herd animals like cows, goats, or sheep are sacrificed for human consumption. Few humans want to be part of that kind of herd.

How did herd immunity enter the language of public health? The phrase seems to have first appeared in the work of American livestock veterinarians concerned about “contagious abortion”—epidemics of spontaneous miscarriage—in cattle and sheep. By the 1910s, it had become the leading contagious threat to cattle in the USA. Farmers destroyed or sold affected cows. Kansas veterinarian George Potter realised that this was the wrong approach. Writing with Adolph Eichhorn in 1916 in the Journal of the American Veterinary Medical Association, he envisioned “herd immunity”. As he wrote in 1918, “Abortion disease may be likened to a fire, which, if new fuel is not constantly added, soon dies down. Herd immunity is developed, therefore, by retaining the immune cows, raising the calves, and avoiding the introduction of foreign cattle.”

“Frontispiece, no. 1. The human herd: Greenwich Hospital Schoolboys at dinner” in Active Immunization Against Diphtheria: its Effect on the Distribution of Antitoxic Immunity and Case and Carrier Infection (1934) by Sheldon F Dudley, Percival M May, and Joseph A O'Flynn

2020 Medical Research Council/Special Report Series, No 195/London: HM Stationery Office/1934

Potter's concept reached the UK in 1917 and 1920 in summaries in Veterinary Review and Scottish Agriculture. It arrived at a crucial moment. Armies and navies struggled against infections throughout World War 1. Medical professionals worked to identify and treat pathogens, and also to understand their population ecology. How did pathogen virulence and population resistance drive the rise and fall of epidemic waves? In The Lancet in July, 1919, bacteriologist W W C Topley described experimental epidemics he created in groups of mice. Unless there was a steady influx of susceptible mice, the rising prevalence of immune individuals would end an epidemic. In a 1923 article in the Journal of Hygiene, he and G S Wilson described this phenomenon as “herd immunity”.

The idea moved into medicine. In 1922, Topley suggested a parallel between outbreaks in mice and children: “Such a likeness would seem to exist in the case of epidemic diseases affecting children of school age.” He also wondered whether measures already “in vogue in dealing with epidemics among live-stock, where methods of segregation are so much more easily enforced than among human populations”, might inform decisions about school closings amid epidemics.

Topley's musings soon found their test. In 1923 Sheldon Dudley, professor of pathology at the Royal Naval Medical School, became aware of epidemics of diphtheria at the Royal Hospital School in Greenwich. The school provided laboratory-like conditions, with a homogeneous group of male students, in good physical shape, who entered in batches several times a year, where they slept in dormitories of 70 to 126 beds. Dudley studied these students and complemented his data with studies from the Grand Fleet during the war and from the training ship HMS Impregnable (grievously susceptible, it turned out, to epidemics).

Dudley published reports for the Medical Research Council on diphtheria and scarlet fever, droplet infections, and diphtheria immunisations. He believed that Topley's analysis of “experimental epidemics among communities of mice provides at more than one point striking parallels to the observed phenomena among the boys at Greenwich”. In a 1924 article in The Lancet, Dudley applied “herd immunity” to humans. In a 1929 article, “Human Adaptation to the Parasitic Environment”, he wrote, “I will now consider the community, or the herd…Nations may be divided into urban or rural herds. Or we can contrast the shoregoing herd with the sailor herd, or herds dwelling in hospitals can be compared with those who live in mental hospitals.”

Dudley's glide from animal to human drew on established British traditions of animal symbolism. As historian Harriet Ritvo argues in The Animal Estate, animals have long served in England as figures for representing national types, lineages, and identities. When Dudley, as surgeon, researcher, and medical administrator, wrote of the “English herd”, he tacitly invoked his own role in a project of national stewardship. Dudley's language, however, did give some readers pause. He prefaced his 1934 report, Active Immunization Against Diphtheria, with photographs of “The human herd” (Greenwich boys at dinner) and “The bacterial herd” (colonies of diphtheria on culture media). As a commentator in The Lancet noted, “Anyone with a modern sense of social progress might well wonder whether the phrase ‘the human herd’ is here used in a scientific or in ironical sense, but perhaps in this case the meanings are not far apart.” Such musings notwithstanding, “herd immunity” became a fixture of epidemiology by the 1930s. Discussions of herd immunity for influenza, polio, smallpox, and typhoid appeared in textbooks, journals, and public health reports in England, Australia, and the USA. The idea also intersected with eugenic notions of racial difference at a time when eugenic racism was ascendant in the UK and the USA. An author of a 1931 Lancet piece wondered whether specific groups, for instance the Maori, had “racial herd-immunity”.

The early researchers never settled on a clear definition. Dudley preferred a focus on what share of a herd had acquired resistance from natural exposure or immunisation. Topley elaborated a more expansive concept. As he explained in the Journal of the Royal Army Medical Corps in 1935, herd immunity encompassed not just the distribution of immunity, but also the social factors determining the herd's exposure. The “English herd”—those living in England—had herd immunity to plague, malaria, and typhus because they no longer lived in close association with the requisite vectors.

Herd immunity took on fresh prominence in the 1950s and 1960s as new vaccines raised crucial questions for public health policy. What share of a population had to be vaccinated to control or eradicate a disease? The idea surged again after 1990 as public health officials worked to achieve sufficient levels of vaccine coverage. But the language of “herd immunity” continued to resonate with visions of people being treated as animals to be domesticated and culled—anxieties reflected in dystopian fiction about farmed humans, from H G Wells' Time Machine to David Mitchell's Cloud Atlas. The association between livestock and sacrifice could have contributed to the objections in March to policies that would have asked many people to be sickened or killed by SARS-CoV-2 in pursuit of herd immunity.

The phrase, however, has not disappeared. Publics face the same problem with COVID-19 in 2020 that Dudley faced with diphtheria in the 1920s: whether a contagious droplet infection can be controlled, without a vaccine or therapeutic, through social distancing and hygiene alone. Studies in June and July cast doubt on prospects for herd immunity: despite months of exposure, antibody surveys found a low seroprevalence, less than 10%, in cities in Spain and Switzerland. Commentators in The Lancet concluded that “In light of these findings, any proposed approach to achieve herd immunity through natural infection is not only highly unethical, but also unachievable”. Sceptics raised other concerns, observing that other coronaviruses induce only transient antibody defences. Defenders of herd immunity, however, have persisted. Some argue that antibodies are not essential because SARS-CoV-2 might induce durable T-cell immunity. Others speculate that if the most susceptible members of a community are infected first, then herd immunity might be achieved after exposure of just 20% of the population.

With potential vaccines still likely to be many months away, and with lockdowns and social distancing causing social and economic disruption, there are no ideal options. British public health expert Raj Bhopal likened the situation to being in zugzwang, “a position in chess where every move is disadvantageous where we must examine every plan, however unpalatable”. He sought to overcome the animal connotations of “herd immunity” by encouraging the use of “population immunity” instead. Changing the label of herd immunity might remove the connotations but not fix the problem. Without a vaccine, many people would have to die from COVID-19 before population immunity is achieved.

COVID-19 mortality in the UK and the USA has already taken a disproportionate toll on poor and minority groups, a reflection of systemic racism and poverty. At one urgent care centre in a largely Latino, working-class neighbourhood in New York City—named, remarkably, Corona—68·4% of antibody tests came back positive. But it remains unclear whether these antibodies will protect individuals or generate herd immunity. Until there exist vaccines that can do both of those things, societies will need to continue to try to control the spread of the virus at the local level through public health measures and community action, to protect the most vulnerable people, and to support public health and medical systems. We should not simply put our faith in the immunity of our herd. Yes. 

Corruption

 2021/03/17 David Lifshultz: Rebuttal The 'Not-So-Hidden Agenda' Behind Bossche's Concern Over 

 COVID Mass Vaccination – Children Health Defense

You do it right.

The very concept of vaccines is erroneous. It is useful to circulate his views as it might put a brake on the current madness but as to whether this fellow is worthwhile the truth is that he is a fool. The key problem is the destruction of the immune system by artificially polluted air, water (fluoride), agricultural (chemical fertilizers), inorganic food pollution, and inorganic medicines just to name a few artificial contrivances. It used to be that the lack of good hygiene which was caused by stupid people was giving us the most serious diseases as small pox, diphtheria, and other diseases but finally the fools woke up. The fools of today create the pollution by producing inorganic and toxic, inorganic foods, etc. Disease is not natural. It is a punishment for wrong actions. Nature is not responsible for causing disease but we are. “Our faults, dear Brutus, lie not in our stars but in ourselves” (Julius Caesar, Act I, Scene III, L. 140-141).

We do not believe in the evil spirit concept of medicine as explained by George Bernard Shaw and Count Lev Nikolayevich Tolstoy even though it is now given a new face as a germ or virus. We think as Shaw that doctors are just as corrupt as politicians. They want their swimming pools, grass tennis courts and Mercedes Benz Maybachs. So they want to force everyone to take a dangerous genetic vaccine to make pharmaceutical companies another trillion dollars against the Nuremberg Laws. When I did a study of the Influenza vaccine, I found that it had no effect on the prevention of the disease though Americans received 200 million shots a year and Gates may have seen it as he shortly after agreed. I did not discuss how many people may have died from the vaccine. Gates and Fauci are to me the new angels of death as Josef Mengele. They should be tried for crimes against humanity for everyone who dies from these vaccine.

Ecclesiastes 7:29 (KJV) Lo , this only have I found , that God hath made man upright; but they have sought out many inventions.

Behind the scenes, companies helping big Covid-19 vaccine makers are getting rich

By Olivia Goldhill  March 25, 2021

Pfizer and Moderna aren’t the only vaccine money-makers. Much of the revenue and profits from Covid-19 vaccines are flowing behind the scenes, going to the contract manufacturers and clinical-trial organizers that turn the shots from lab-bench theory to mass-produced reality.

Both AstraZeneca and Johnson & Johnson publicly committed to not profiting off their products during the pandemic — though AstraZeneca has reserved the right to declare the pandemic over on July 1, even if the World Health Organization has not. Pfizer and Moderna made no such pledge, with Pfizer expected to make $15 billion in vaccine-related revenue this year, while Moderna is forecasting $18.4 billion in vaccine sales.

在幕后，帮助大型Covid-19疫苗生产商的公司开始致富

 由奥利维亚·戈德希尔（Olivia Goldhill）2021年3月25日

 辉瑞和Moderna并不是唯一赚钱的疫苗。  Covid-19疫苗的大部分收入和利润都在幕后，流向合同制造商和临床试验组织者，使制造商从实验室工作台理论转变为大规模生产的现实。

 阿斯利康和强生公司都公开承诺在大流行期间不会从其产品中获利-尽管阿斯利康保留了在7月1日宣布大流行的权利，即使世界卫生组织没有宣布。 辉瑞和Moderna没有做出这样的承诺，辉瑞今年的疫苗相关收入预计为150亿美元，而Moderna的疫苗销售额预计为184亿美元。

 In their greed these teachers will exploit you with fabricated stories. Their condemnation has long been hanging over them, and their destruction has not been sleeping.

They will be paid back with harm for the harm they have done. 

 I have written as reminders to stimulate you to wholesome thinking. 

Therefore, dear friends, since you have been forewarned, be on your guard so that you may not be carried away by the error of the lawless and fall from your secure position.