Initial coronavirus vaccines may come with limitations, according to Robin Shattock, an Imperial College London professor leading development of an experimental shot.
There are concerns that desperation to keep economies open amid the coronavirus pandemic could lead to settling for a vaccine that prevents sick or death but does not necessarily keep them safe from catching the coronavirus.
“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 gradually lift their lockdowns, leaders searching for a preventive shot as the path to go back to pre-pandemic life. With funds in government investment, vaccines from companies like China’s CanSino Biologics Inc. and huge corporations like Pfizer Inc. and AstraZeneca Plc are in development.
One of the experimental shots has already conducted human trials after revealing an effect on severe disease, but less so on infection, in animals.
“Vaccines need to protect against disease, not necessarily infection,” said Dennis Burton, an immunologist and vaccine researcher at Scripps Research in La Jolla, California.
Drawbacks
However, such coronavirus vaccines might promote 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.”
The World Health Organization said that vaccines are among the most effective ways to combat an infectious disease and prevent up to 3 million deaths a year.
More than 130 shots
Vaccines become effective when it presents the immune system with a form of a germ and prepare the body to respond when a real exposure takes place.
However, coronavirus vaccine may not provide long-term immunity, according to White House health advisor Dr. Anthony Fauci. He expressed his worry about the vaccine’s “durability.”
He said that if Covid-19 persists like other coronaviruses, “it likely isn’t going to be a long duration of immunity.”
“When you look at the history of coronaviruses, the common coronaviruses that cause the common cold, the reports in the literature are that the durability of immunity that’s protective ranges from three to six months to almost always less than a year,” said Fauci, director of the National Institute of Allergy and Infectious Diseases, said during an interview with JAMA Editor Howard Bauchner.
Preventing serious disease
The US Food and Drug Administration is looking into 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 reportedly protect individuals against infection with the pathogen that causes the disease but have been presented to protect against symptomatic disease, Felberbaum said.
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.”
