Will We Achieve COVID-19 Herd Immunity And End The Pandemic?

Herd Immunity and Its Function

What is herd immunity? It is a term used when the transmission of an infectious disease is prevented as a result of the majority of the population in a community having an immunity to the cause of an infectious disease.

The function of this group's immunity is to stop the spread of an infectious disease that could potentially bring down a community in a very short time. Such immunity can only be obtained and achieved if the majority of the population in a community gets vaccinated or immunized against the disease. 

According to the John Hopkins School of Public Health, depending on the type and the rate of infection of a disease, it is estimated between 50% and 90% of the population needs to be immunized in order to achieve herd immunity.

Examples of Herd Immunity

The term “herd immunity” was first used around the 1910s by the veterinarian, George Potter. It was then used in the medical field around the 1920s when diphtheria was an epidemic at the time. In addition to diphtheria, among the diseases that are successfully eliminated by vaccines and later formed herd immunity are:

• Smallpox, caused by the variola virus

• Polio, caused by the poliovirus

• Whooping cough or pertussis, caused by the bacteria Bordetella pertussis

• Measles, caused by measles virus

Most of these diseases were especially common among children, but are rarely encountered today due to vaccination at an early age. These are just a few examples of the various diseases that have been successfully eradicated due to vaccination and herd immunity. Herd immunity is effective in protecting a community where the majority of its population is immunized. 

COVID-19 and Herd Immunity

There are two ways to achieve herd immunity:

• By exposing a population to the disease. However, this is an unethical method to obtain herd immunity. In the context of COVID-19, a population who does not practice physical distancing or using face masks will increase the rate of infection of the virus to others. This can cripple the health system in place due to the excessive number of infected and will further increase the mortality rate. Sweden was one of the countries that aimed to achieve herd immunity using this method, but it has instead jeopardized its citizen’s safety and put an immense burden on their healthcare system.

• The second method is to vaccinate a majority of the population. Apart from vaccination, living with a new norm such as wearing face masks, physical distancing and practicing and maintaining good hand hygiene will help a lot in preventing the spread of the virus. 

For COVID-19 herd immunity, various measures need to be planned and carried out by all parties so that they can be achieved and reduce the rate of infection and daily cases. Although the Movement Control Order (MCO) has been implemented for the second time, we can still see an increase in daily cases and this means that the rate of infection is still at a high level. Therefore, this immunization program against the COVID-19 virus is necessary and needs to be implemented to slow down the rate of infection.  

Can We Achieve COVID-19 Herd Immunity?

The western part of Australia is said to be temporarily free from the outbreak and its citizens are free to move without the use of face masks and physical distancing after very strict movement control orders previously were enforced. A similar situation can be seen in New Zealand. 

Vaccination and the implementation of new norms are the best measures to prevent the spread of the COVID-19 for now. Our country will receive a supply of COVID-19 vaccine from various pharmaceutical companies and this vaccine supply will be given out to 80% of the Malaysia population and will be given in stages as outlined in the National COVID-19 Immunization Program which has started at the end of February this year. 

When can a community expect to achieve herd immunity? It depends on the value of the reproduction number (R0 or R-naught). So what is R0? R0 tells on average how many individuals who are not yet immune to the COVID-19 virus can be infected by an individual who is positively tested for COVID-19. The higher the R0 value, the more people need to be immunized to achieve group immunity and lower the virus infection rate. 

According to the World Health Organization (WHO), studies on immunity to the virus are still ongoing and the percentage or how many populations need to be vaccinated to prevent the spread of COVID-19 is still unknown.