By Mary Hearty

COVID-19 vaccines are not only protective against getting severe disease, they also prevent getting infected in the upper respiratory tract, according to Dr Katherine O’Brien, Director of the World Health Organization’s Department of Immunization, Vaccines and Biologicals.

“It looks like they might, even if you do get infected, also reduce the period of the infection. Early data also shows that when you are infected in your respiratory tract, you might have less of the virus than if you are not vaccinated. And each of these things would reduce the likelihood that you would transmit that virus to someone else,” Dr O’Brien explained during a WHO virtual interview.

She emphasized that these are still early findings: “We only have one or two studies. Besides, we are yet to have results for each of the vaccines that are now out there. It is for this reason that people need to continue wearing masks and follow other interventions that are keeping us safe and reducing transmission.”

Moreover, the Epidemiologist noted that mostly used vaccines around the world have substantial effectiveness for most variants. Nevertheless, they may not be as effective as they are against the non-variants.

She revealed that more variants will continue to emerge because that is what viruses do. So the vaccine manufacturers are clearly going to and already adapting to try to make them as best they can be against a range of variants, as we scientists continue to learn more about how those variants interact with the vaccines.

Additionally, she recommended that those who have had COVID-19 disease should still get a full dose of the vaccines. “So if it is a vaccine that requires two doses, you should get the two doses.”

She added: “We certainly have seen evidence that a single dose of vaccine, especially in people who have had COVID-19 disease in the past, gives a really strong antibody response, and that is really good news. It shows that the vaccine is boosting the immunity that has developed as a result of the illness that they had.”

At the moment, there is no scientific evidence about whether or not a single dose following disease would be fully protective or equally protective against the variants that have already emerged, and the duration of protection.

“So without evidence to really assure people that a single dose is going to give you durability of protection and optimum protection against variants, we still recommend you go ahead and get both doses of vaccines,” she said.