Despite countries the world over rolling out immunisation programmes, herd immunity is unlikely to be achieved this year according to the World Health Organization (WHO).
“We are not going to achieve any levels of population immunity or herd immunity in 2021,” said WHO chief scientist Dr Soumya Swaminathan. This is despite the “incredible progress” made by vaccine manufacturers which has enabled tens of millions of inoculations globally. As of January 13th, Bloomberg reports that over 30.5 million people have received shots in 43 countries.
Herd immunity, as explained by the WHO, refers to “the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection.
“WHO supports achieving ‘herd immunity’ through vaccination, not by allowing a disease to spread through any segment of the population, as this would result in unnecessary cases and deaths. Herd immunity against COVID-19 should be achieved by protecting people through vaccination, not by exposing them to the pathogen that causes the disease.”
It goes on to note that “the percentage of people who need to be immune in order to achieve herd immunity varies with each disease. For example, herd immunity against measles requires about 95 percent of a population to be vaccinated. The remaining five percent will be protected by the fact that measles will not spread among those who are vaccinated. For polio, the threshold is about eighty percent.
“The proportion of the population that must be vaccinated against COVID-19 to begin inducing herd immunity is not known. This is an important area of research and will likely vary according to the community, the vaccine, the populations prioritized for vaccination, and other factors.”
India is gearing up for its own vaccination campaign, one which has been deemed the world’s largest and carries a price tag of US$7 billion. First off, thirty million frontline workers including healthcare staff are to be targeted. This will be followed by roughly 270 million people aged over fifty and/or with underlying conditions amplifying their risk.
“The new year has brought with it another big achievement,” Prime Minister Narendra Modi said earlier this year. “India’s scientists have successfully developed not just one, but two made-in-India COVID vaccines. In India, the world’s largest COVID vaccine programme is also about to begin. For this, the country is very proud of the contributions of its scientists. Every countryperson is indebted to all our scientists and technicians.”
Nonetheless, herd immunity is not yet on the horizon – at least in 2021. Measures such as physical distancing and the wearing of face coverings are likely to remain in place as a result.
Swaminathan urged patience, stating rollout of vaccines on this scale “does take time.” She said “it takes time to scale the production of doses, not just in the millions, but here we are talking about in the billions.” Swaminathan assured that “the vaccines are going to come…but meanwhile we mustn’t forget that there are measures that work.” Such measures will have to be followed for “the rest of this year at least,” she added.