Covishield vaccine gap reduced for travellers; here's what we know about the gap extension rules

A day after ramping up vaccination pace in the country, the Ministry of Health has once again recommended a change in the vaccination schedule of Covishield, one of the primary vaccines being administered country-wide.

The dosing gap, which was previously extended to 84 days (or 12-16 weeks time gap), will now allow people in specific categories to receive the vaccine dose earlier, 28 days after getting the first dose of the COVID-19 jab. As per the new rules, people who have undertaken the first shot of the vaccine, and are seeking international travel (for employment/education/part of the Olympics contingent) will now be allowed to get fully vaccinated and get the second dose before the 84-day mandate rule if their travel dates fall before the stipulated timeline.

Covishield dosing gap revised: When can you actually get your jab?

While the government officials have stressed on making rigorous checks, the newest recommendations also bring about newer questions and challenges for those who have received the Covishield jab- Will it be safe to take the vaccine early? How less 'immune' are you, in comparison to the 84-day mandated gap? As we explain to you how the newest change in the vaccination gap would affect people, here's a timeline of the gaps ordered with Covishield in India...

As part of the SOPs issued for people travelling outside of India, the centre has now retweaked vaccination guidelines for people receiving Covishield, or the Oxford-Astrazeneca vaccine to get their second dose earlier than stipulated. The newest changes would mean that people no longer have to wait for 12-16 weeks to get their second dose, but instead, will be able to get the dose within a 28-day interval, which is the original waiting period in place for Covishield.

ALSO READ: Possible side-effects of Covishield vs Covaxin vs Sputnik V

While Covishield, unlike Covaxin is internationally approved and accepted, concerned authorities believe that the move will allow vaccinated beneficiaries to travel safely outside India, without encountering any hiccups, and at the same time, minimize the risk of infection post vaccination as we continue to be engulfed with news about fast-spreading mutant virus strains.

That being said, the change in policy will not be applicable to everyone who has been inoculated with the Covishield vaccine- only beneficiaries whose travel dates fall before the 84-day window and subject to important travel concerns will be allowed to get vaccinated early. Others, who have previously taken Covishield vaccine or scheduled to get one will still be "allowed" to get the second dose of the vaccine 12-16 weeks afterwards.

The current revision in the Covishield dose gap pertains to special cases only. However, the 84-day interval was fixed after recommendations from the National Technical Advisory Group on Immunisation (NTAGI) found that the prolonged waiting window will allow more Indians to get partially vaccinated right now.

Apart from that, the extended vaccination window, according to researchers and case studies, also makes the vaccine work more effective and doles out strengthened antibody response. Clinical data, based out of India and abroad have also made a case for a heightened immune response when the second dose of the vaccine is injected many weeks after the first one.

The most positive findings have been supported by a study published in the Lancet, which proved that vaccine efficacy and immune response were also a great derivative of the time gaps. Researchers found that with certain COVID vaccines, including Covishield, the longer the gap, the higher the efficacy of the vaccine. It was observed that the vaccine efficacy and immune response was significantly better, at 81.3% when the doses were given in an interval of 12-16 weeks, in comparison to a 50-60% efficacy when spaced 6 weeks or less apart.

It should also be known that this isn't the first time the vaccination gap with Covishield has been extended. While the initial policies kept the dosing window between 4-6 weeks time, it was later revised to 4-8 weeks, following which, the gap was further extended to the 12-18 week timeline.

The gap with Covaxin, and other vaccines expected to be used in India remain unchanged.

While the change in guidelines do allow some people to get the second dose early, it is also subjected to concerns about the vaccine becoming "less effective" or mounting lesser immunity if taken early.

Similar concerns were raised with earlier recommendations when people who had previously received doses early thought they would be less protected. Although perplexing, taking the vaccine early, or even too late doesn't render it ineffective. What may only change is the percentage of protection offered. The only difference being, an extended window may showcase a relatively higher antibody and immune response than before, and serve a larger purpose of driving up community-wide immunisation at a critical juncture like right now. Remember, the vaccine is equally effective in both scenarios.

There can also be a possibility that despite relaxation of norms may not be able to get the second dose on time or have to travel early. Those with a history of illness (post the first shot) will also be suggested to delay second dose vaccination.

In such cases, a person will only be considered partially vaccinated and may be required to undergo quarantine and testing mandates, internationally. However, as new studies have claimed, Covishield offers a much-strengthened response with the first dose, in comparison to Covaxin, since it mounts more antibodies. Thus, there's still some level of protection that may be granted to a partially vaccinated individual.

However, getting both doses of the vaccine are still important, and should be scheduled when and where possible to gain all benefits of full vaccination.

The Oxford-Astrazeneca vaccine, which is one of the strongest vaccines under offer, has been approved for use in several countries globally including the UK, parts of Europe, Sri Lanka, Canada. The revision in the timeline is also being followed globally, in different ways.

For example, both UK and Canada which are using the vaccine offer an extended gap of upto 4 months, similar to what is being followed in India. In other places, trials of mixing and matching different vaccines are also being studied to understand possible scenarios and benefits.