Second thoughts on mass vaccination

Elon Musk famously remarked that he and his family would not take the Covid-19 vaccine. Coming from a celebrity multibillionaire and entrepreneur, such a statement is likely to promote vaccine hesitancy among many. On the other hand, the unprecedented second wave with reports of scarcity of oxygen and hospital beds have led to desperation among the masses, who believe that mass vaccination will halt the pandemic in its tracks. This is evident from crowds at vaccination centres and frequent crashing of the CoWIN, the online site for registration.

Both extreme positions, outright rejection of vaccine by public figures on one hand, and on the other the craze to get vaccinated by the masses, can adversely affect our fight against the pandemic.

Vaccine is a strong and powerful weapon against the novel coronavirus, a marvel of modern precision and genomic technology. And like all strong weapons it should neither be withheld nor used indiscriminately but should be deployed strategically to derive maximum benefit in a cost-effective way. The generals of the war against the pandemic should be conversant with the benefits as well as the hazards of this artillery, the vaccine.

Regrettably, nobody is paying heed to these ground realities, in spite of sane counsel by experts. Dr N K Arora, Head, Operations Research Group at Indian Council of Medical Research (ICMR), wrote an opinion piece dated April 12, 2021, in the Times of India, titled, "Opening up vaccines for younger adults right now will be a gamble with lives."

He went on to explain the logistic challenges and the science behind this strategy. He stated that it would have made perfect sense to vaccinate all adults if we lived in a utopia with infinite resources. However, the reality is that we are in the midst of a raging pandemic with finite supplies of vaccines. The aim should be to reduce deaths and hospitalization from the infection.

There is limited evidence that current vaccine can interrupt transmission and young adults without comorbidites rarely land up in hospital or die from the infection. So, vaccinating young adults given the present constraints will not be cost effective. What needs to be done is to prevent deaths, the majority of which occurs in the older age groups. Dr Arora also warned about the possibility of emergence of mutant strains as a result of mass and indiscriminate vaccination campaigns.

Makes perfect sense. However subsequent events indicate little heed is being paid to logic and science in this pandemic. Any opposition to mass vaccination is likely to be labelled as "vaccine hesitancy. Bureaucrats and scientific advisers to the government would not like to be stigmatized thus, and fearing repercussions, would tend to remain silent. Group think prevails in this environment and everyone feels secure on the bandwagon.

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According to the third round of National Level Serosurvey, about 21% of our population had already encountered the virus during the first wave. Given the speed of spread of the second wave and its scale, it is very likely that another 30-50% of the population will be infected before the vaccine reaches them. So, at the end of the second wave, we can expect about 50-70% of our population to have reached some level of population immunity due to natural infection. There is no scientific logic to vaccinate those who have recovered from natural infection.

There are other issues related to mass vaccination which can lead to vaccine hesitancy among the masses. If millions are vaccinated at fast pace with limited resources for monitoring and surveillance of adverse events following vaccination, there are likely to be some adverse events, and deaths which may be purely coincidental and not related to the vaccines. Even so, common perception would attribute it to the vaccine leading to vaccine hesitancy. This will be a setback which would make it difficult to administer vaccine to even the vulnerable.

To practice and follow hard science we should go for country wide serosurveys once the second wave is over for estimating the population level immunity. We should refrain from vaccinating those with antibodies and also those who have had a positive RT-PCR report in the past.

This can save a lot of vaccines and resources which can be focused on those who really need the vaccine such as health care workers, front line workers, the elderly and people with obesity and co-morbidities. To continue the science, we can follow large cohorts who have recovered from past infections to see whether they get re-infected. We can always revise our vaccination policy guided by science if we find an appreciable number of re-infections which are serious enough.

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The pace in the present pandemic is like running a marathon at the speed of a sprint. Everything from the diagnostic test on which so many policy decisions have been and continue to be taken, lockdowns, most treatment regimes, and now the vaccines developed at warp speed, have been on emergency use authorization and unprecedented in the history of public health.

The medical consensus has reached the last lap of this marathon, or thinks it has, the finishing line being eradication. Politicians and the public alike think that the vaccines will eradicate the coronavirus. But history of public health does not support this hope.

Only one disease, smallpox could be eradicated more than 150 years after arrival of its vaccine. It was a disease which required no sophisticated diagnostic test, did not have subclinical and asymptomatic infections, cases could be identified and isolated even by the common people and the smallpox virus did not infect animals. None of these criteria applies to the coronavirus.

Given these realities, it is time to take a pause in this marathon, and revise our strategy based on science and common sense and not based on tunnel visions of laboratory scientists, however brilliant, and political expediencies.

Towards this end, an open letter from top scientists in the country, published on 29 April asks the government for access to databases on Covid-19 testing. Data captured by government agencies like the ICMR can drive evidence based public health policy. Data on age, location, health and vaccination status of everyone who submits a sample for Covid-19 test should be made easily accessible. Such data can help prioritize groups for vaccination, help us understand the role of concurrent illnesses, and enable evaluation of the efficacy of vaccines.

(The writer is Professor & Head, Community Medicine and Clinical Epidemiologist at Dr DY Patil medical college, Pune)