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KOLKATA

Infected after 2nd shot? Vax still best bet: Doctors | Kolkata News

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KOLKATA: A handful of people who have taken both shots of the Covid vaccine — mostly healthcare workers — has subsequently tested Covid-positive, but experts have said that this should neither be taken as any indication of the vaccine’s inefficacy, nor a reason to shy away from the jab altogether. A few vaccinated people catching the virus is usual, they say, pointing out that not one of them got seriously sick, only because of the vaccine.
The only way to beat the pandemic, especially the surging second wave, is through mass vaccination, the experts say, while pointing out the importance of Covid-appropriate behaviour.
The most important thing to keep in mind is that a vaccine does not guarantee instant protection, says Shanta Dutta, director, ICMR-NICED, Kolkata. “It could take as long as three weeks for a recipient to develop sufficient immune response,” she says, adding, “That is the reason why one has to stick to all Covid-19 safety protocol, even after receiving the second shot.” A 42-year-old lab technician attached with AMRI Dhakuria tested positive 15 days after the second shot of Covishield. Two such cases were reported at Peerless Hospitals. Apollo Gleneagles Hospitals has also had two such cases, and Rabindranth Tagore International Institute of Cardiac Sciences (RTIICS) has had one. At Medica, two doctors are currently in home quarantine after testing positive.
“None of the two cases in our hospital needed hospital care,” says Sudipta Mitra, the CEO of Peerless Hospital.
The two vaccines currently being administered have efficacy rates ranging between 70% (Covishield) and 80% (Covaxin). But there are things to remember, says immunologist Dipyaman Ganguly, scientist, Indian Institute of Chemical Biology (IICB), Kolkata. “Efficacy of protection is expected to be optimum after at least two weeks past the second dose,” he says. “In fact, the efficacy seems to be far better in real life than reported in the original data. Post-vaccination infections do not seem to be that high. But given the kind of efficacy, failure in about 20% to 30% cases is anyway expected,” he adds.
We should remember that mass vaccination is the only way to curb and counter the second wave, says internal medicine specialist Syamasis Bandyopadhyay, director, medical services, Apollo Gleneagles Hospitals. “Since none of the vaccines assures 100% protection, about a third of those vaccinated may still get the infection. more so if they shun standard precautions.
Only two healthcare workers have needed hospital care, but none needed critical care support.
Pharmacology and vaccinology expert Santanu Tripathi, former professor at School of Tropical Medicine, Kolkata, says transmissibility is currently very high, especially with mutated versions of the virus around. “A small portion of people will get infected even after the second dose if they lower the guard. But even in those cases, the vaccine is expected to lower the severity of infection, thus lowering hospitalisation needs and ultimately reducing mortality. We need to collect more robust post-vaccination data,” he adds.
A matter of concern, though, is that a very few got infected well past a month of receiving the second dose. A 66-year-old matron with Shusrusha Nursing home, who got the second dose of Covishield on March 2, was found infected on April 7. A support staff at RTIICS got infected 25 days after the second dose, whereas a healthcare worker at Peerless Hospital contracted the virus one-and-a-half months past the second dose.
“Oxford University research has shown that a later second dose, at 12 weeks, is much more efficacious,” says Ganguly. “But in India most vaccine recipients who have already received both doses, had received the second dose much earlier. Perhaps the protection was not robust after an early second dose.”

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