If a person gets COVID-19 after the first dose, when should they get the next vaccine?

The story so far: Despite a massive shortage of COVID-19 vaccines across the country, the central government has announced that vaccination for all people over 18 will start from May 1. But several state governments have expressed their inability to launch the program citing a vaccine shortage. They postponed the campaign until the necessary stocks arrived in each state. This could have a profound impact on the epidemiological health of a population gripped by a deadly second wave of infections.

How big is the shortage?

India currently produces around 2 million vaccines per day, and according to data from the Co-WIN portal, the number of vaccines administered daily is around 2.3 million to 2.5 million. The shortage is glaring. Technically, the production capacity is lower even than the daily needs.

As of April 29, 9.1% of the population had received a dose of the vaccine and only 1.9% had been “fully vaccinated”. This leaves out a large part of the population who is still not vaccinated.

Chandrakanth Lahariya, vaccinologist and epidemiologist, says the calculations behind this are indisputable. “Even at current production levels, demand is higher. Vaccination has been opened to the additional population and the demand has tripled, while the supply remains the same.

He explains that even though other manufacturers are licensed to produce vaccines and a few million doses of the Russian Sputnik vaccine are expected shortly, increasing production will take time. The Serum Insititute of India, the maker of Covishield, is looking to ramp up production to 100 million doses per month in the near future, and Bharat Biotech, which makes Covaxin, is talking about producing 50 to 60 million doses per month. But even in the coming months, production is unlikely to significantly exceed 150 million doses per month.

Can people extend the interval for their second dose?

The two vaccines available in India have a two dose schedule. For Covishield, the AstraZeneca vaccine, T. Jacob John, renowned virologist, formerly at Christian Medical College, Vellore, said: “Phase 3 trials have been conducted in many countries at varying intervals. They felt that a second dose 12 weeks later provided the best protection. Studies with an interval of six to eight weeks have also shown a linear relationship, with efficacy improving over time. In times of non-emergency, the best option is to take the second vaccine at 12 weeks, but faced with the second wave, he warns, however, that patients should take the vaccine on time to reduce the risk for themselves.

The second dose of Covaxin can be taken four to six weeks after the first.

Read also | Can people test positive for COVID-19 even after inoculation?

Dr Lahariya says India is expected to increase the gap for Covishield to 12 weeks. Any vaccination schedule is based on technical and operational feasibility, he says. In routine childhood immunization, most vaccines are given with an interval of four weeks in India, while in many countries abroad they are given after an interval of eight weeks. “The operational reason here is that the coverage is already low. If we increase the vaccine deficit, it could delay vaccination unnecessarily, especially for DTP. We must therefore design our immunization program on the basis of scientific evidence and operational needs. At Covishield, the greater the gap, the greater the proven effectiveness. And several million doses will be saved to allow people to take at least one injection.

However, this scenario cannot be extrapolated to Covaxin, adds Dr Lahariya. At this point, the advice would be to encourage people to receive doses whenever they can. “Regardless of when the second dose is taken, it matters,” he says.

Immunologically, it is understood that when a person has received a vaccine (even a dose), the immune system is activated. This means the system may have a better response than a naive immune system in an unvaccinated person, says Dr Lahariya.

If a person gets COVID-19 after the first dose, when should they get the next vaccine?

According to Dr Lahariya, the broader principle is to delay vaccination. “Natural infection offers some protection for a few months. If a person has already received an injection within a month, the natural infection becomes a kind of booster infection. Given the operational challenges, delaying the second shot can be done with enough confidence. However, the decision should be left to the people. “

Dr. John highlights the evolution of guidelines published by the US Centers for Disease Control and Prevention (CDC). “Originally the CDC came up with a three-month gap, then changed it to a one-month gap, and finally we have, I think, some advice to take anytime after full recovery, or after the person has become completely asymptomatic. “