Tweaked COVID vaccines in testing try to fend off variants

A large number of Americans are rolling up their sleeves for a third dose of COVID-19 vaccine -- this time around, shots tweaked to protect against a worrisome mutated version of the virus.

Make no mistake: The vaccines becoming rolled out over the U.S. offer strong protection. But new studies of experimental updates to the Moderna and Pfizer vaccines mark a crucial first step toward an alternative if the virus eventually outsmarts today’s shots.

“We need to be prior to the virus,” said Dr. Nadine Rouphael of Emory University, who's helping to lead a report of Moderna's tweaked candidate. “We know very well what it's like when we're behind.”

It isn't clear if or when protection would wane enough to require an update but, "realistically we want to turn COVID right into a sniffle,” she added.

Viruses constantly evolve, and the world is in a race to vaccinate millions and tamp down the coronavirus before a lot more mutants emerge. A lot more than 119 million Americans experienced at least one vaccine dose, and 22% of the populace is fully vaccinated, based on the Centers for Disease Control and Prevention. Much of all of those other world is far behind that pace.

Already an easier-to-spread version found in Britain just months ago is becoming the most frequent variant now circulating in america, one that’s luckily vaccine-preventable.

But globally, there's concern that first-generation vaccines may offer less protection against a different variant that first emerged in South Africa. All of the major vaccine makers are tweaking their recipes in the event an update against that so-called B.1.351 virus is necessary. Now experimental doses from Moderna and Pfizer are being put to the test.

In suburban Atlanta, Emory asked persons who received Moderna's original vaccine this past year in a first-stage study to also help test the updated shot. Volunteer Cole Smith said returning wasn’t a hardcore decision.

“The earlier one, it had been an excellent success and, you understand, millions of people are receiving vaccinated now,” Smith told The Associated Press. “If we’re helping people with the old one, you will want to volunteer and help people with the new one?”

The analysis, funded by the National Institutes of Health, isn’t just testing Moderna’s experimental variant vaccine as a third-shot immune booster. Researchers at Emory and three other medical centers are also enrolling volunteers who haven’t yet received any kind of COVID-19 vaccination.

They would like to know: Could persons be vaccinated just with two doses of the variant vaccine rather than the initial? Or one dose of every kind? As well as get the initial and the variant dose combined in to the same injection?

Separately, the meals and Drug Administration has given Pfizer and its German partner BioNTech permission to get started on similar testing of their own tweaked vaccine. The firms called it part of a proactive strategy to enable rapid deployment of updated vaccines if they’re ever needed.

The Moderna and Pfizer vaccines, similar to COVID-19 vaccines being used all over the world, train the body to recognize the spike protein this is the outer coating of the coronavirus. Those spikes are the way the virus latches onto human cells.

Mutations occur whenever any virus makes copies of itself. Usually those mistakes make no difference. But if a whole lot of changes accumulate in the spike protein -- or those changes are in especially key spots -- the mutant might escape an disease fighting capability primed to watch for an intruder that looks a little different.

The good thing: It’s fairly simple to update the Moderna and Pfizer vaccines. They’re made with a bit of genetic code called messenger RNA that tells the body how to make some harmless spike copies that subsequently train immune cells. The companies simply swapped out the initial vaccine’s genetic code with mRNA for the mutated spike protein -- this time around, the main one from South Africa.

Studies getting underway this month add a few hundred people, completely different than the massive testing had a need to prove the original shots work. Scientists must make sure the mRNA substitution doesn’t trigger different unwanted effects.

On the protection side, they’re closely measuring if the updated vaccine prompts the immune system to produce antibodies - which fend off infection - as robustly as the original shots do. Importantly, tests can also show if those antibodies recognize not merely the variant from South Africa but other, more prevalent virus versions, too.

Some good news: Antibodies aren't the only defense. NIH researchers recently looked at another arm of the disease fighting capability, T cells that fight back after infection sets in. Tests showed T cells in the blood of people who recovered from COVID-19 long before worrisome variants appeared nevertheless recognized mutations from the South African version. Vaccines trigger T cell production, too, and may be key to protecting against the worst outcomes.

Still, no vaccine is 100% effective - even without the mutation threat, occasionally the fully vaccinated are certain to get COVID-19. Just how would authorities know an update is necessary? A red flag will be a jump in hospitalizations - not only positive tests - among vaccinated people who harbor a new mutant.

“That’s when you’ve crossed the line. That’s when you’re discussing a second-generation vaccine,” said Dr. Paul Offit of Children’s Hospital of Philadelphia, a vaccine adviser to the Food and Drug Administration. “We haven’t crossed that line yet, but we might.”