Groping in the dark on booster doses

Though over 1.26 billion doses have been administered as on December 4 with nearly 85% receiving one dose but only over 50% being fully vaccinated. Over 8% of health-care workers, 30% of those above 60 years and over 33% of people aged 45-59 years are yet to be fully vaccinated. And there is no scientific evidence in India to support a booster dose.

On November 22, Director-General of ICMR said that no scientific evidence was available thus far to administer a booster vaccine dose to people who are fully vaccinated. The priority instead was on increasing the percentage of people who are vaccinated with two doses. The health minister too said the priority was on fully vaccinating all adults than on immunising people with a booster shot though adequate vaccines were available.

Even when clamour from a few States for booster doses increased once the new variant with higher transmissibility causing a huge surge in cases in South Africa became known, the government has reiterated that any decision on booster doses will be based solely on scientific recommendations.

Even as over 65 million people in the U.S. are unvaccinated, on October 21, a booster shot was approved for all above 65 years and certain categories of young adults. A month later, it was expanded to include all adults. Many countries in Europe too have approved booster shots. Many of those countries have based their decision at least partially on vaccine effectiveness data. Such evidence has become available in India only very recently.

Just one study for each vaccine 

One study found Covishield to be 85% protective against moderate or severe disease and 63% protective against symptomatic infection, while another study found Covaxin to be 50% effective against symptomatic infection. Both studies were undertaken during the peak of the second wave driven by the Delta variant.

The effectiveness of both vaccines against the Omicron variant is unknown. While the Omicron variant appears to be far more transmissible than the Delta variant, the disease severity and the age groups that are most vulnerable to disease are not fully known.

Despite these uncertainties, it might still be prudent to approve booster doses for people older than 60 years and young adults who are immunocompromised or have comorbidities. But administering booster doses cannot be at the cost of increasing the coverage of first dose and full vaccination. Also, the need to begin immunising adolescents cannot be ignored.

Only 50% fully vaccinated

Over 1.26 billion doses have been administered as on December 4 with nearly 85% receiving one dose but only over 50% being fully vaccinated. Though the door-to-door vaccination campaign held last month witnessed 11.7% increase in second dose coverage, there is still a sizable percentage of population belonging to the priority groups who are not fully vaccinated. Over 8% of health-care workers, 30% of those above 60 years and over 33% of people aged 45-59 years are yet to be fully vaccinated.

Like the mad scramble for vaccines seen for several weeks after the Delta variant emerged, the rapid global spread of the Omicron variant might lead to increased vaccine uptake in the months to come. While sufficient supply of Covishield, which accounts for nearly 90% of vaccines administered, might be able to meet the increased demand, the priority should be to increase vaccine coverage and not boosters, particularly so as India will be pressured to supply vaccines to the global South.

Published in The Hindu on December 6, 2021