Covid: As new variants emerge, is herd immunity impossible?
International desk || shiningbd
Herd immunity is a term that has been bandied around since the beginning of the coronavirus pandemic. It occurs when a large proportion of a population becomes protected against or immune to infection, significantly reducing the spread of that infection even in the unprotected group.
It can be achieved through the following:
Natural infection: when enough of a population has caught the infection and built up naturally acquired antibodies to the disease that protect against infection in the future
Vaccines: when enough people in a population have been vaccinated against a disease, allowing them to build up protective antibodies, without the need for infection, that are effective in protecting against serious infection in the future
When it comes to COVID-19, we know that trying to aim for herd immunity through natural infection can have devastating consequences. We have seen how the virus can rip through countries, leading to more than 4.3 million deaths worldwide to date.
Not only this, it can cause serious illness in the acute phase, and impact lives and livelihoods with the effects of long COVID. We also do not know how effective antibodies acquired through natural infection are, or how long they last, and there are many cases of people catching the coronavirus more than once.
Vaccines, on the other hand, have successfully controlled contagious diseases such as smallpox, polio, diphtheria, pertussis, rubella and many others without the need for people to get sick. Whereas it is not uncommon for those vaccinated against COVID to experience mild, short-term side effects after getting their shot, unvaccinated people are far more likely to develop the severe illness if they catch the virus.
We know that vaccines offer better protection than natural infection, with antibodies lasting longer and being more effective against serious illness. The World Health Organization (WHO) supports achieving herd immunity through vaccination, not by allowing disease to spread through any segment of the population, as this would result in unnecessary cases and deaths.
It is also worth noting that the route taken towards “herd immunity” through vaccination is important; it is vital that the most at-risk groups in a population are vaccinated first as these people stand to lose a lot should they get infected.
In the case of COVID, this means vaccinating the elderly and those with underlying health conditions first – offering them a level of protection while herd immunity is being achieved.
Although it makes sense to try to achieve herd immunity through vaccination programmes, there are challenges. First, just like naturally acquired antibodies, we are unsure how long protection from vaccine-induced antibodies will last, and more research is needed to ascertain whether the vaccines help reduce transmission of the virus.
Then, there is the matter of vaccine hesitancy and the spread of misinformation, which is preventing large numbers of people from taking up the vaccine.