Omicron risks spark calls for booster doses
Experts divided on extra protection for few over ensuring universal immunisation
The United States and the United Kingdom have approved booster doses for all adults, six months after the completion of their second dose. In the UK, however it is restricted to those 40 and above, or those with a clinical conditions that supress their natural immunity.
These recommendations build from research suggesting that two weeks after a booster, the chances of being protected from symptomatic COVID increases.
A study in Israel also suggests that immunity against infection dips noticeably in the six months after two doses of the Pfizer/BioNTech vaccine.
Compared to people who got only two doses five months prior, those who got three doses of the vaccine had 93% lower risk of COVID-19-related hospitalisation, 92% lower risk of severe COVID-19 disease, and 81% lower risk of COVID-19-related death. Vaccine effectiveness appeared consistent across sexes and age groups (ages 40-69 and 70+) and number of comorbidities.
“With Omicron, the Government of India must, without any delay, make it possible for all senior citizens and those with co-morbidities irrespective of age, to get a third or ‘booster’ dose of the relevant vaccine. In fact the Government should enable, encourage and assist them in getting that on a war-footing. Not doing that would be a policy folly of the first magnitude,” Gopalkrishna Gandhi, 76, former Governor of West Bengal told The Hindu.
Harsh Mahajan, president, NATHEALTH, a healthcare body which raises issues on access and quality of healthcare, said it was presumed that there was unused stock of between five and 10 million doses in the private sector in India which would likely start expiring from 2022 January to February.
Dr. Mahajan added that in case the expert committee of the Government decided that a booster dose was necessary, then this stock could be used for boosters for healthcare and frontline workers and those who were at higher risk despite having received two doses. “The objective should be to minimise wastage of this precious resource,” he told The Hindu previously.
However, not everyone is convinced that booster doses are necessary for India. Public health expert and epidemiologist Chandrakant Lahariya said the real risk of approving booster doses in India now would mean that it would divert attention away from the more important goal of ensuring as many Indians were inoculated by the year end.
He added that all the studies on booster doses so far were specific to mRNA vaccines. Since none of these are being administered in India, it would be prudent to conduct those studies, arrive at a reasonable lower bound of vaccine efficacy beyond which a third dose would be necessary, if at all, and then proceed, Dr Lahariya said.
“At this stage when only 30% of Indians are fully inoculated and half of those above 45 still weren’t vaccinated, it’s unreasonable to demand a third dose for otherwise healthy senior citizens,” he told The Hindu. “All evidence shows the vaccines are extremely effective against severe disease and hospitalisation. Transmission can only be addressed by COVID appropriate behaviour. In Europe and the U.S., the bulk of hospitalisation is among the unvaccinated,” he pointed out.
He said that it wouldn't be imprudent of the Indian government, if it had surplus stock, to divert vaccines to Africa which has vaccinated less than a quarter of its population. “The pandemic can end only when most of the world is fully vaccinated and not a small set of people getting multiple doses,” Dr .Lahariya said.
He however, added that there was a case for administering booster doses for the immunocompromised.
A study by the Translational Health Science Institute, Faridabad, published last week in the Lancet Infectious Diseases, reported that two shots of Covishield gave 63% protection against symptomatic SARS-CoV-2 infection and 85% protection against moderate or severe disease. It also found that there wasn’t significant reduction in cellular immunity even when some of the patients were afflicted by more infectious variants such as Delta.
This category of immunity, also called T cell immunity, results from the body learning to destroy the coronavirus after having being taught to do so from either a vaccination or a previous infection and is considered more long lasting than the protection conferred from neutralising antibodies which are produced within weeks of an inoculation or infection.