Dozens of Americans are rolling up their sleeves for a third dose of COVID-19 vaccine – this time shots have been adapted to protect against a worrying mutated version of the virus.
Make no mistake: the vaccines currently being rolled out in the US offer strong protection. But new studies on experimental updates of the Moderna and Pfizer vaccines are a critical first step towards an alternative if the virus finally surpasses today’s shots.
“We need to advance the virus,” says Dr. Nadine Rouphael of Emory University, who is helping lead a study of Moderna’s tweaked candidate. “We know what it’s like when we’re behind.”
It’s not clear if the protection would be enough to require an update, but: ‘realistically, we want to make COVID in a sniff,’ she added.
Viruses are constantly evolving and the world is vaccinating millions and bumping up the coronavirus before even more mutants emerge. More than 119 million Americans have had at least one vaccine dose, according to the Centers for Disease Control and Prevention, and 22% of the population is fully vaccinated. Much of the rest of the world is far behind the pace.
Already an easily spread version found in Britain a few months ago has become the most common variant now being distributed in the United States, one that fortunately cannot be prevented by vaccine.
But worldwide, there are concerns that first-generation vaccines may offer less protection against another variant that first emerged in South Africa. All major vaccine manufacturers are adapting their recipes for an update of the so-called B.1.351 virus. Experimental doses of Moderna and Pfizer are now being tested.
In suburban Atlanta, Emory asked people who received Moderna’s original vaccine a year ago in a first-stage study to test the updated shot as well. Volunteer Cole Smith said returning was not a difficult decision.
“The previous one, it was a huge success and millions of people are being vaccinated now,” Smith told The Associated Press. “If we help people with the old, why not help volunteers and people with the new?”
The study, funded by the National Institutes of Health, not only tests the experimental variant of Moderna’s vaccine as a third-shot immune booster. Researchers at Emory and three other medical centers are also enrolling volunteers who have not yet received any form of COVID-19 vaccination.
They want to know: Can humans only be vaccinated with two doses of the variant vaccine and not with the original? Or a dose of any kind? Or even the original dose and the variant dose are combined in the same injection?
Separately, the Food and Drug Administration gave Pfizer and its German partner BioNTech permission to launch similar tests of their own custom vaccine. The companies call it part of a proactive strategy to enable rapid vaccination of updated vaccines if ever needed.
The Moderna and Pfizer vaccines, like most COVID-19 vaccines used around the world, train the body to recognize the peak protein that is the outer layer of the coronavirus. These nails are how the virus adheres to human cells.
Mutations occur when any virus makes copies of itself. Usually those mistakes make no difference. But if there are a lot of changes in the ear protein accumulating – or if the changes occur especially at key sites – the mutant can escape from an immune system prepared to pay attention to an invader that looks a little different.
The good news: it’s pretty easy to update the Moderna and Pfizer vaccines. They are produced with a piece of genetic code called messenger RNA, which tells the body how to make harmful copy copies that in turn train immune cells. The companies simply exchanged the genetic code of the original vaccine with mRNA for the mutated ear protein – this time the one from South Africa.
Studies underway this month include several hundred people, which is very different from the massive testing needed to prove the original shots work. Scientists need to make sure that replacing mRNA does not cause various side effects.
On the protective side, they carefully measure whether the updated vaccine is requesting the immune system to produce antibodies – which ward off infection – as strongly as the original shots. It is important that laboratory tests can also show whether these antibodies not only recognize the variant from South Africa, but also other, more common virus versions.
Good news: antibodies are not the only defense. NIH researchers recently looked at another arm of the immune system, T cells that fight back after infection begins. Laboratory tests have shown that T cells in the blood of people who recovered from COVID-19, long before worrying variants, nevertheless appeared recognized mutations from South Africa. version. Vaccines also cause T cell production and can be the key to preventing the worst results.
No vaccine is still 100% effective – even without the mutation threat, the fully vaccinated will occasionally get COVID-19. How, then, would authorities know that an update is needed? A red flag is a leap in hospitalizations – not just positive tests – among vaccines that have a new mutant.
“That’s when you crossed the border. This is when you talk about a second-generation vaccine, ‘says Dr. Paul Offit of Philadelphia Children’s Hospital, a vaccine advisor from the Food and Drug Administration. “We have not crossed that border yet, but we have.”