COVID-19: Should the gap between vaccine doses be increased?
India kicked off the crucial second phase of its massive inoculation drive against the coronavirus on Monday. Currently, the prescribed interval between the two doses of Oxford University and AstraZeneca's Covishield in India is four weeks or 28 days. However, a number of experts around the world have called for stretching this gap to up to three months. Here are more details on this.
Global studies suggest increasing gap between doses
Last month, the World Health Organization's (WHO) advisory group SAGE had suggested that there should be an 8-12-week interval between two doses of the COVID-19. On February 19, The Lancet published results of a study that showed that the Covishield may have a higher efficacy when administered with a three-month interval as compared to a six-week interval.
'20-30% greater efficacy achieved by stretching gap'
Scientific evidence from across the globe shows that there is 20-30% greater efficacy by stretching the interval between two doses, vaccine scientist Dr. Gagandeep Kang told The Indian Express. "So why would we not want to do that?"
Increasing gap can help more people receive jabs
According to experts, increasing the interval between the vaccine jabs will allow the government to give doses to more people as well as increase exports of vaccines. "The government should very seriously consider this. A 20% increase in efficacy when you give it to millions of people is tens of thousands of new infections prevented," Dr. Kang said.
But can the first dose provide enough protection?
The first dose of Covishield can provide 76% protection for the three months between the doses, The Lancet study finds. "There is ample evidence from the Lancet paper that one gets pretty good short-term protection from the first dose," Dr. Kang told the publication.
SII scientists also support the suggestion
The suggestion to increase the gap has been welcomed by scientists at the Pune-based Serum Institute of India (SII), which is manufacturing the Covishield in India. Further, Dr. Shashank Joshi, expert on Maharashtra's COVID-19 task force, stated that a greater interval will be "ideal." "A gap of four weeks is reasonable but ideally the 8-12 weeks is better," Dr. Joshi was quoted as saying.
However, some experts advise caution
However, some experts have advised caution in relying only on observational studies for such a decision. Prof. Sanjay Rai, President of Indian Public Health Association, said it is better to give the doses in time frame decided by the Centre until more robust evidence is generated. 1.56 crore vaccine doses have been administered so far in India, according to the government data released today.
