How COVID-19 vaccine could end up helping virus spread

*It may be possible to infect others even after getting a shot as the vaccinated people might stop wearing masks and observe physical distancing since they are not themselves at risk anymore

Isola Moses | ConsumerConnect

A vaccine that protects against symptoms of the novel Coronavirus (COVID-19) pandemic could contribute to the spread of the disease if—and this is still just an if—the people who get vaccinated remain capable of carrying and transmitting the virus.

ConsumerConnect learnt that is a risk that’s got little attention amid the deserved jubilation over a November 9, 2020, report from Pfizer Inc. and BioNTech SE that their vaccine candidate appears to be highly effective.

Report says it’s a matter of timing. If everyone in the world is vaccinated, or has developed antibodies through exposure to the disease, there will be no problem.

However, in the early going, when only some people are protected, they could unwittingly spread the disease to people who are still vulnerable. How?

The vaccinated people might stop wearing masks and observe physical distancing since they are not themselves at risk anymore.

They could be carrying the SARS-CoV-2 virus, even if they’re not getting sick from it.

How big a problem this might be is hard to say, because we don’t know for sure if immunised people are capable of shedding infectious virus.

It’s possible that their antibodies will eradicate any infection pretty quickly, so they might just shed viral debris.

It is yet unclear how much protection the Pfizer-BioNTech vaccine and others would provide, according Bloomberg report.

The gold standard is to achieve sterilising immunity, which is so strong that the virus cannot get a grip in the body at all—meaning that vaccinated people are safe to others.

The human papillomavirus vaccine provides sterilising immunity, for example. But sterilising immunity is hard to achieve with viruses such as SARS-CoV-2, which enter through the respiratory system.

The only sure way to know if the vaccine provides sterilising immunity would be to check whether trial subjects who remain free of COVID-19 have been exposed to it, by tracing their contacts.

The Pfizer-BioNTech vaccine and others might provide just functional immunity—protecting people from the full-blown disease, but not from carrying the virus. Functional immunity may also be what people get from being infected by the disease itself.

They can catch it again, but will have fewer, if any, symptoms. We already know that people who are asymptomatic can spread COVID-19. In fact, that’s one of its scariest characteristics.

The issue was raised with Paul Griffin, a professor in the Faculty of Medicine at the University of Queensland, in Australia.

Griffin, who is an investigator on four COVID-19 vaccines that do not include the Pfizer-BioNTech one, said that while it might turn out that vaccinated people can transmit the disease, transmission is far more likely if people are coughing and sneezing.

“So, if we are preventing clinical disease, then that will go a long way to reduce transmission as well, even if it’s not precisely a transmission-blocking vaccine,” Griffin said recently.

Under the right conditions, a vaccine can and should suppress the transmission of COVID-19.

But if people who get vaccinated throw caution to the winds, it is possible they could get a lot of other people sick, according to report.

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