India reduces gap for coronavirus booster shot from 9 months to 6

The Union Health Ministry on Wednesday reduced the gap for taking a Covid-19 precaution shot or a booster shot after the primary two doses to six months from an earlier nine months.

In a letter to all states, Union Health secretary Rajesh Bhushan said in view of ‘evolving scientific evidence and global practices’ the Standing Technical Sub-Committee (STSC) of the National Technical Advisory Group on Immunisation (NTAGI) has recommended to reduce the gap between second dose and precaution dose to 6 months or 26-weeks from an earlier 9 months or 39 weeks. The NTAGI too has endorsed the same.

“Therefore, it has been decided that the precaution dose for all beneficiaries from 18-59 years will be administered after completion of six months, or 26 weeks from the date of administration of the second dose at a private vaccination centre," the letter said.

The government is administering precaution doses for free for those above 60 years, healthcare and frontline workers. Corresponding changes have been made in the CoWIN system to facilitate the new dispensation.

“Instructions may be issued to all the officials concerned and it might also be publicised widely,” Bhushan wrote. 

In mid-June, the standing technical sub-committee members agreed to reduce the gap between the second and the third doses of Covid-19 vaccine. Now, the NTAGI has recommended the same, and the Union Health Ministry has advised states to vaccinate accordingly.

Meanwhile, in the wake of another major mutation in the Sars-CoV-2 virus – BA.2.75 – experts bat for heterologous boosting or mixing vaccines for the booster dose. Shahid Jameel, senior research fellow at Green Templeton College at Oxford University, told Business Standard that the BA.2.75 has several mutations in the spike protein, of which two are unique when compared to its parent strain BA.2. These two mutations are G446S and R493Q.

The senior researcher feels that G446S is one of the most potent sites of escape from antibodies made by current vaccines that still neutralise BA.2. “So it increases chances of infection in people so far protected,” he says.

Besides advocating booster shots for the vulnerable, Jameel also says that India should use science to update booster policy. “The current policy is not making the best use of evidence and available vaccine choices,” he says, adding that recent data from CMC, Vellore study on mixing Covishield and Covaxin shows that Covishield after Covaxin is a far superior combination, but India continues to use third dose Covaxin in people who got two doses.

“Also global data shows protein vaccines are better after 2 doses of AZ vaccine than a 3rd dose,” Jameel says.