At a press conference on Monday, World Health Organization Chief Scientist Dr. Soumya Swaminathan said that there is not enough evidence that the new COVID vaccines prevent infection.
Dr. Swaminathan said "I don't believe we have the evidence on any of the vaccines to be confident that it's going to prevent people from actually getting the infection and therefore passing it on."
"I'm interested in your views on how you think the vaccine will work in the context of elimination?" A reporter from the Sydney Morning Herald asked.
The reporter noted that countries in her region have done well with elimination, but asked "what does that mean, in the long term, where people are vaccinated overseas. Does that ensure that they are not a risk travelling to countries that have almost zero community transmission? Or do you think that those who have been vaccinated will still need to quarantine if they're going to countries that have low transmission?"
"I think that's a really important question," Dr. Swaminathan replied, "and I think that what we're learning now and we continue to wait for more results from the vaccine trials, is to really understand if these vaccines, apart from preventing symptomatic disease and severe disease and deaths, whether they are also going to reduce infections, or preventing people from getting infected with the virus, precent them from passing it on or transmitting it to others.
"I think that at the moment, I don't believe we have the evidence on any of the vaccines to be confident that it's going to prevent people from actually getting the infection and therefore passing it on. I think until we know more, we need to assume that people who have been vaccinated also need to take the same precautions until there's a certain level of herd immunity, of course, that's been built into the population.
"This is a dynamic and evolving field. Our understanding and our recommendations will change as we get more follow up data from these trials."
Her colleague Dr. Michael Ryan agreed. "I think it's really important, he said, "that we also reflect on the main objective of the vaccine in the first roll out will be to prevent severe illness, prevent deaths, to protect front line workers and vulnerable people in our society."
He said that he hopes the vaccine is first offered to health care workers globally, and that the "first and primary objective is to decrease the impact that this disease is having on people's lives, and therefore that will be a major step forward in bringing the world back to some kind of normal."
Ryan said that "I think we should be able to get good control of the virus," but that full elimination required a "much higher degree of efficiency and effectiveness in the vaccination programme."