COVID-19 vaccine manufacturers are figuring out how to change their prescriptions against worrying virus mutations – and regulators are looking for the flu as a plan, if and when photos need an update.
“It’s not something you can change in a way, do overnight,” warned Richard Webby, who runs a World Health Organization flu center at St. John’s Children’s Research Hospital. Jude.
Viruses move constantly and you only need the right combination of special mutations to escape vaccination. But studies raise concerns that first-generation COVID-19 vaccines do not work as well against a mutant that first appeared in South Africa, as well as against other versions circulating around the world.
The good news: Many of the new COVID-19 vaccines are made with new, flexible technology that is easy to upgrade. What’s harder: Deciding if the virus has moved enough that it’s time to change the vaccines – and what changes to make.
“When do you pull the trigger?” asked Norman Baylor, former head of the Food and Drug Administration’s vaccine. “This is a moving target right now.”
FLU PROVIDES A MODEL
The WHO and the FDA are looking at the global flu vaccine system to decide how to treat similar decisions about COVID-19 vaccines.
The flu moves much faster than the coronavirus, and flu vaccines need to be adjusted almost every year. National centers around the world collect circulating influenza viruses and monitor their evolution. They send samples to WHO-designated laboratories for more sophisticated “antigenic” tests to determine the potency of the vaccine. WHO and the regulators then agree on the vaccine’s prescription for that year, and the producers get to work.
For COVID-19 vaccines, Webby said a critical step is to establish a similar surveillance and testing network to signal the mutations that matter. Today, there is great geographical variability in tracking and testing moved versions. For example, the United Kingdom does more testing of the changing viral genome than the United States
Three variants first discovered in the UK, South Africa and Brazil are worrying because of the combinations of mutations that make them more contagious.
On Sunday, US researchers reported a still different mutation found in seven variants that appeared in several states. No one still knows if this mutation makes the virus easier to spread, but the report, which has not yet been verified by other scientists, calls for further research to find out.
HOW COVID-19 IS REIGNED
Just because a variant is more contagious does not mean that it will also be impervious to vaccination. But the variant first identified in South Africa is worrying. David Ho of Columbia University introduced blood samples from people who received the Pfizer or Moderna vaccines into laboratory vessels with the mutant virus. The antibodies produced by the vaccine are still protected, but they were much less potent.
Preliminary test results from two other vaccine candidates – Novavax and Johnson & Johnson – soon supported these findings. Both were still protected, but were weaker when tested in South Africa, where that variant predominates, than when tested elsewhere. A much smaller test of the AstraZeneca vaccine in South Africa has raised questions about its effect.
“If the virus could make an extra mutation or two, it could escape even more,” Ho warned.
TRUE DEAR
If fully immunized people begin to be hospitalized with the mutant virus, “then the line is crossed,” said Dr. Paul Offit, a vaccine expert at the Children’s Hospital of Philadelphia who advises the FDA.
That has not happened yet, but “we should prepare,” he added.
Modern is about to explore an option: Could a third dose of the original vaccine boost immunity enough to avoid some variants, even if it’s not an exact match?
Columbia’s Ho said it’s a good idea to test, because people can “have another pillow in abundance” if their overall antibody levels are very high.
ADJUSTMENT OF RECIPES
Large manufacturers are also developing experimental vaccine variants, just in case.
COVID-19 vaccines produce antibodies that recognize the spike protein that covers the coronavirus. When the virus moves, sometimes the protein spike changes into key areas, making it harder to recognize vaccine-produced antibodies.
Pfizer and Moderna vaccines are made with a piece of genetic code called messenger RNA that tells the body how to make a few harmless copies of the spike protein that drives immune cells. To update the vaccine, they can simply change the payload: change the original genetic code with mRNA for the mutated spike protein.
The AstraZeneca vaccine and the Johnson & Johnson vaccine, which is expected to be launched soon, are made with cold viruses designed to inject a spike protein gene into the body. Vaccine adjustment requires the growth of cold viruses with the mutant gene, which is slightly more complex than the mRNA approach, but not as laborious as reformulating old-fashioned flu vaccines.
The Novavax vaccine, also in the final stage test, is made with a laboratory-grown copy of the spike protein, which could also be modified to suit mutations.
VACCINE TESTING 2.0
First-generation COVID-19 vaccines have been tested on tens of thousands of people to make sure they work and are safe – research that took many months.
Simply changing the prescription to better target viral mutations will not require repeating these studies in thousands of people, Dr. Peter Marks, head of the FDA vaccine, recently told the American Medical Association.
The FDA is still finalizing the requirements, but Marks said the agency intends to be “quite agile.” If an updated vaccine is needed, testing on several hundred people would probably be enough to tell if it triggers a good immune response, he said.
But an even bigger question: if only some places face vaccine-resistant virus mutants, would the authorities want vaccines with only variants or vaccines to protect against two types in one jab? After all, flu vaccines protect against three or four different types in one go.
Companies should first do some basic research to make sure that an exclusively variant version properly invigorates the immune system, said John Grabenstein, a former Merck Vaccine executive of the Coalition for Action on Immunization. Then, a combined photo would require several tests to make sure there is an equal answer to both types.
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The Associated Press Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.