First vaccines may not prevent you from getting virus
Desperation for a way to keep economies from collapsing under the weight of COVID-19 could mean settling for a vaccine that prevents people from getting really sick or dying but doesn’t stop them from catching the coronavirus.
Although a knockout blow against the virus is the ultimate goal, early vaccines may come with limitations on what they can deliver, according to Robin Shattock, an Imperial College London professor leading development of an experimental shot.
“Is that protection against infection?” Shattock said. “Is it protection against illness? Is it protection against severe disease? It’s quite possible a vaccine that only protects against severe disease would be very useful.”
As countries emerge warily from lockdowns, leaders are looking to a preventive shot as the route to return to pre-pandemic life. Fueled by billions of dollars in government investment, vaccines from little-known companies such as China’s CanSino Biologics and giants such as Pfizer and AstraZeneca are in development.
At least one of the fastestmoving experimental shots has already advanced into human trials after showing an impact on severe disease — but less so on infection — in animals. Experts say such a product would probably be widely used if approved, even if that’s as much as it contributes, until a more effective version comes to market.
“Vaccines need to protect against disease, not necessarily infection,” said Dennis Burton, an immunologist and vaccine researcher at Scripps Research in La Jolla, Calif.
There are drawbacks, though. While holding the potential to save lives, such vaccines might lead to complacency in lockdown-weary nations, said Michael Kinch, a drug development expert who is associate vice chancellor at Washington University in St. Louis.
“My guess would be that the day after someone gets immunized, they’re going to think, ‘I can go back to normal. Everything will be fine,’ ” he said. “They’re not going to necessarily realize that they might still be susceptible to infection.”
COVID-19 is already thought to be spread by people without symptoms, and a symptom-preventing vaccine may create even greater numbers of them.
In their attempts to confront a rapidly growing threat, developers are turning to technologies that have never been used successfully in humans. More than 130 shots are in the works for COVID-19 prevention, according to the World Health Organization.
The U.S. Food and Drug Administration is considering options for a vaccine that prevents illness.
“We would potentially consider an indication related to prevention of severe disease, provided available data support the benefits of vaccination,” FDA spokesman Michael Felberbaum said in response to questions. “For licensure we would not require that a vaccine protect against infection.”
Licensed vaccines including some against whooping cough have not been demonstrated to protect against infection with the pathogen that causes the disease but have been demonstrated to protect against symptomatic disease, Felberbaum said.
The notion of using imperfect vaccines and therapies is “fine,” Kinch said. “That’s just practicality. And we may follow those up with more-perfect. There will never be a truly perfect vaccine.”