Issues and Significance of Longer Vaccine Gaps

Synopsis: Recently, the government introduced longer vaccine gaps for few reasons. But it fails to take other things into account.

Introduction:

Recently the Indian government recommended a higher interval between two doses of the Covishield vaccine. Apart from that, the government also introduced few other changes. Such as,

• Encouraging lactating women to take vaccines
• 3-month waiting period before taking vaccines for the Covid-19 recovered persons (earlier it was four to eight weeks).
• If the person gets Covid-19 infections after the first dose, s/he also needs to go through a three-month waiting period before taking the second dose of Covid-19 vaccine.
• Increasing the vaccine gap between two doses from 12-16 weeks for Covishield.

Two underlying principles behind longer vaccine gaps:

1. To tackle the shortage in the vaccine:
   • Prior to second-wave, the government focussed on vaccinating vulnerable sections and frontline workers.
   • But during the second wave, the government allowed vaccine manufacturers to ‘free up’ vaccine supply. Under this, they can sell only 50% to Center and the rest on their own. But this policy did not improve access to all citizens.
   • So, the government introduced the higher vaccine gap.
2. Best timing of the second dose for an optimal boost to the immune system:
   • Clinical trials of the AstraZeneca vaccine in the UK (18-55 years) showed that the binding antibodies (the ones that actually block viruses) were nearly twice high for persons who got their vaccine shots after 12 or more weeks.
   • Further, the vaccine also appeared to be more protective for persons above 18 with a longer dose interval.

Challenges with longer vaccine gaps:

A general policy for childhood vaccines in India is 4 to 8-week intervals. So, the 12-16 week difference is not a general one. Further, it also has many concerns. Such as,

• Antibody levels are one of the key markers of protection. But, they are not the only ones. Cell-based immunity (immune system confers long-lived immunity) is not considered in scientific studies.
• Duration of protection: At present, there is huge uncertainty about the duration of protection given by vaccines. For example, there are many pieces of evidence that exist for breakthrough infections and Covid-19 related deaths even after the second dose of vaccination. So, only more vaccination will provide greater clarity on the degree of protection.

Way forward:

The death tolls from India’s second wave continue to surpass similar daily figures from the U.S. and Brazil. Further, the policymakers have to remember that many Indians have still not been exposed to the virus and newer threatening variants are on the line.

So the government has to aim for universal vaccination to prevent disease spread and death toll. The government has to accelerate vaccination drives and policy recommendations geared towards that goal.

Source: The Hindu