The first generation of COVID-19 vaccines may not prevent people from becoming infected with or transmitting SARS-CoV-2 virus (COVID-19). According to Anthony Fauci, MD, director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and other infectious disease experts, the best that COVID-19 vaccines may do is prevent people becoming severely ill and dying.
“It’s quite possible a vaccine that only protects against severe disease would be very useful,” said Robin Shattock, PhD, professor of mucosal infection and immunity at Imperial College London.1 Dr. Fauci agrees. Regarding the experimental AZD1222 vaccine (formerly known as ChAdOx1 nCoV-19) being developed by Oxford University and biopharmaceutical company AstraZeneca plc, Dr. Fauci said:
I would have liked to have had protection against infection. But then again, it depends on what you’re looking for with the vaccine. That vaccine doesn’t look like it’s a knockout for protecting against infection, but it might be really very good at protecting against disease.1 2 3
AstraZeneca Unsure AZD1222 Vaccine Will Clear SARS-CoV-2
In a recent interview with the BBC, AstraZeneca CEO Pascal Soriot said that although it is unclear if their vaccine would “completely clear the virus,” he believes that it could still be considered effective if it kept people from getting COVID-19 symptoms. “The question around the vaccine is will some patients need a second dose and also will the vaccine eliminate the virus from the body of the people or simply protect them against being sick. But being protected against being sick would already be a big plus,” Soriot said.4
“That’s really important,” said BBC interviewer Andrew Marr, who added, “But it’s possible that this vaccine will stop you going to hospitals, stop you from getting pneumonia and becoming very ill, but will allow the virus to carry on transmitting through the community until it reaches someone who hasn’t been vaccinated.”
Soriot did not dispute that possibility. He noted that that it wasn’t clear how contagious a person with the SARS-CoV-2 virus would be [after getting vaccinated] and stated:4
Even if the vaccine doesn’t eliminate the virus from the body of every single person we’ve vaccinated, the question will be, how long will the virus stay in the body… maybe people take a little longer to get rid of it. And the other question will be, if the [virus] is still there in your nose, can you be contagious, can you infect someone else or not? Those are questions we don’t have answers for yet.4
Are Vaccines That Don’t Prevent Infection Considered Effective?
The problem with vaccines that will not actually prevent SARS-CoV-2 viral infections is that most people who get vaccinated will assume they are protected and will not take any further precautions either for themselves or to prevent transmission to other people.
According to Michael Kinch, PhD, director of the Center for Drug Discovery at Washington University in St. Louis, Missouri, “My guess would be that the day after someone gets immunized [for COVID-19], they’re going to think, ‘I can go back to normal. Everything will be fine.’ They’re not going to necessarily realize that they might still be susceptible to infection.”1
1 Lauerman J, Paton J. The First Covid Vaccines May Not Prevent Covid Infection (1). Bloomberg Law June 15, 2020.
2 Aakash B, Faulconbridge G, Holton. U.S. secures 300 million doses of potential AstraZeneca COVID-19 vaccine. Reuters May 21, 2020.
3 Branswell H. Anthony Fauci on Covid-19 reopenings, vaccines, and moving at ‘warp speed’. STAT June 1, 2020.
4 The Andrew Marr Show. Pascal Soriot: ‘Quite confident coronavirus vaccine will work. BBC May 24, 2020.