WASHINGTON (AP) – Dozens of Americans are rolling up their sleeves to get a third dose of COVID-19 vaccine; this time, the features have been adjusted to protect against a worrying mutated version of the virus.
Make no mistake: Vaccines currently being rolled out in the United States offer strong protection. But new studies on experimental upgrades to the Modern and Pfizer vaccines mark a critical first step toward an alternative if the virus far exceeds current shots.
“We need to stay ahead of the virus,” said Dr. Nadine Rouphael of Emory University, who is helping lead a study on Moderna’s modified candidate. “We know what it’s like when we’re back.”
It’s unclear if or when protection will decrease enough to require an upgrade, however, “we really want to turn COVID into a blowout,” he added.
Viruses are constantly evolving and the world is in a race to vaccinate millions and curb the coronavirus before even more mutants appear. More than 119 million Americans have had at least one dose of vaccine and 22% of the population is fully vaccinated, according to the Centers for Disease Control and Prevention. Much of the rest of the world is far behind this pace.
Already an easier version to spread found in Britain a few months ago has become the most common variant now circulating in the United States, one that fortunately can be prevented with vaccines.
But globally, it worries that first-generation vaccines may offer less protection against a different variant that first appeared in South Africa. All major vaccine manufacturers are tweaking their prescriptions in case an update is needed against the so-called B.1.351 virus. Experimental doses of Moderna and Pfizer are now being tested.
In Atlanta, on the outskirts, Emory asked people who received the original Moderna vaccine a year ago in a first-phase study to also help test the updated shot. Volunteer Cole Smith said returning was not a difficult decision.
“The previous one, it was a huge success and, you know, millions of people are getting vaccinated now,” Smith told The Associated Press. “If we help people with the old, why don’t we volunteer and help people with the new?”
Proactive strategy
The study, funded by the National Institutes of Health, is not just testing the Moderna experimental vaccine variant as a third-shot immune booster. Researchers at Emory and three other medical centers are also enrolling volunteers who have not yet received any type of COVID-19 vaccine.
They want to know: could people be vaccinated with only two doses of the variant vaccine and not the original one? Or a dose of each type? Or even combine the original dose and the variant in the same injection?
Separately, the Food and Drug Administration has given permission to Pfizer and its German partner BioNTech to begin similar testing of its own modified vaccine. Companies have described it as part of a proactive strategy to enable the rapid deployment of up-to-date vaccines if they ever need them.
We have to be ahead of the virus. We know what it’s like when we’re back.
–Dr. Nadine Rouphael, Emory University
Moderna and Pfizer vaccines, like most COVID-19 vaccines used worldwide, train the body to recognize the ear protein that is the outer coating of the coronavirus. These peaks are how the virus attaches itself to human cells.
Mutations occur whenever any virus makes copies of them. Usually, these mistakes make no difference. But if many changes to spike protein are piled up (or those changes are found in especially key places), the mutant could run away from an immune system ready to watch an intruder who looks a little different.
The good news: it’s pretty easy to upgrade to Modern and Pfizer vaccines. They are made with a piece of genetic code called messenger RNA that tells the body how to make copies of harmless spikes that in turn train the immune cells. The companies simply changed the genetic code of the original mRNA vaccine to the mutated spike protein, this time from South Africa.
Studies starting this month include a few hundred people, very different from the massive tests needed to show that the original photos work. Scientists need to make sure that mRNA replacement does not trigger different side effects.
In terms of protection, they are closely measuring whether the updated vaccine causes the immune system to produce antibodies, which defend against infection, in the same way that the original shots do. It is important to note that laboratory tests can also show whether these antibodies recognize not only the South African variant, but also other more common virus versions.
Some good news: antibodies aren’t the only defense. NIH researchers recently examined another arm of the immune system, T cells that shrink after infection. Laboratory tests showed T cells in the blood of people who recovered from COVID-19 long before worrying variants appeared, although the mutations recognized the South African version. Vaccines also cause T cell production and may be key to preventing the worst outcomes.
However, no vaccine is 100% effective, even without the threat of mutation, from time to time those fully vaccinated will get COVID-19. So how would the authorities know that an update is needed? A red flag would be a leap in hospitalizations – not just positive tests – among vaccinated people who have a new mutant.
“That’s when you crossed the line. That’s when you talk about a second-generation vaccine,” said Dr. Paul Offit of Philadelphia Children’s Hospital, a vaccine advisor to the Food and Drug Administration. “We haven’t crossed that line yet, but it’s possible.”
Associated Press journalist Ron Harris in Atlanta contributed to this report.
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