Health officials consider another round of bivalent boosters for the most vulnerable Americans

CNN

According to a source who was not authorized to speak on the matter, US officials are considering whether to offer people at high risk for severe Covid-19 a chance to receive another bivalent booster.

Although most Americans are happy to ignore pandemic warnings, including vaccines, those who want to protect their loved ones or themselves from serious illness have been wondering when they will get another chance.

Michael Osterholm is one of them. He directs the University of Minnesota’s Center for Infectious Disease Research and Prevention.

When the bivalent boosters were introduced in the US last autumn, the 70-year old was quick to receive an updated version. All Americans aged 5 or older should receive the bivalent booster at least 2 months after receiving their last vaccine dose, or 3 months after receiving a Covid-19 injection.

Osterholm, six months after his last booster, asked Osterholm about adding a second bivalent shot to his protection. He said, however, that he was turned down.

Study of the effectiveness and safety of the Covid-19 vaccines has shown that after six months, their immunity to infection, hospitalizations, and emergency room visits diminishes as the blood levels of neutralizing antibodies fall. Although some protection is still available in T-cells (and B-cells), components of the immune system which retain a memory about past invaders, the duration of this protection is not fully understood.

Osterholm caught Covid-19 last week for the first-time.

He said, "I don't know how I caught it." "I was wearing N95s [masks], the entire nine yards.

Osterholm is aware that even with a second bivalent booster, it was possible for him to still get sick. The Covid-19 vaccines do not provide the sterilizing immunity necessary to prevent infection. But he cannot help but wonder if he could have bounced back faster.

He said, "I wonder what it would have been like to get it."

The virus that causes Covid-19 has advanced and outsmarted all passive immunity. Doctors used to give vulnerable patients antibodies to boost their immune defenses. This means vaccines are one of the few safeguards that remain for those most at risk of severe Covid-19 infection.

Bivalent boosters protection may be decreasing

Two types of instructions are included in the bivalent vaccines to aid the body against Covid-19. The first teaches it how to recognize the circulating ancestral strain of Covid-19. The second helps it recognize and defeat the Omicron virus, its descendants.

The US Centers for Disease Control and Prevention have collected data that shows the vaccine update has increased protection.

The shots make people 14 times less likely than those who don't have them and three times less likely than those who did not get them.

Experts who advise the US FDA regarding vaccine decisions suggested that in January, the FDA phase out monovalent vaccines that protect against the ancestral strain and instead give bivalent doses of first shots to Americans who have not had their first Covid-19 vaccines. This would include infants and toddlers.

New data shows that the effectiveness of bivalent vaccines has been beneficial, but that their protection is beginning to diminish just like the boosters.

The shot seems to be 50% more effective in preventing emergency room visits and hospitalizations for adults who have received the new booster within the first two months. This is on top of the limited protection provided by previous shots.

According to data presented by the CDC's Advisory Committee on Immunization Practices at its February meeting, after four months, the protection provided by bivalent vaccines for the same measures drops to a little over 30%.

This trend has led Canada and the United Kingdom to allow certain people to receive a bivalent booster.

The UK's Joint Committee on Vaccination and Immunization recommended in February that additional bivalent boosters should be available at least six months following a previous dose for adults aged 75 and over, seniors living in residential care homes, and anyone older than 12 with suppressed immune function.

According to the Public Health Agency of Canada, adults could be given an additional bivalent shot if their immune system is compromised.

Officials in the US are trying to convince most Americans to get a bivalent booster shot. Since September, only 54 million Americans have been eligible for a bivalent booster. This is less than 1/5th of the eligible population.

The US Food and Drug Administration's Emergency Use Authorization for Bivalent Vaccines does not allow doctors to prescribe another booster to vulnerable patients or for the CDC recommend one.

"We will continue to monitor the emerging data in America and worldwide, and we'll base any decision regarding additional boosters on those data." Individuals who have not received an updated (bivalent booster) are encouraged to talk to their doctor and to consider getting one. This was a statement from the FDA, which was sent to CNN by an FDA spokesperson.

The agency has several options to loosen restrictions on the use bivalent vaccines.

First, the FDA must approve both dual-strain shots. Pfizer, a vaccine manufacturer, requested that the FDA approve dual-strain shots by submitting a supplemental biologics licensing request on February 24. Moderna did not announce a similar move, and they didn't respond to a request.

If granted by the FDA, the FDA will allow the CDC to modify its recommendations regarding boosters and give doctors permission to administer another dose to patients who are most at risk.

Manufacturers of vaccines could also request that the FDA modify its emergency use authorizations to include permissive language, which would allow for a second dose.

Osterholm stated that regardless of the FDA's mechanism, he supports giving patients the option to receive another booster dose if prescribed by their doctors.

Spring boosters are awaited

Many people eagerly await another chance.

"This is the most commonly asked question I receive at the moment," said Dr. William Schaffner of Vanderbilt University, who is an infectious disease expert. It's on the minds of those who think about it very, very carefully.

However, he doesn't see any spring boosters in the US.

Schaffner stated that neither the FDA nor CDC's Advisory Committee on Immunization Practices would make recommendations without data. "And nobody is currently collecting data on yet another bivalent booster as to its effectiveness or safety.

Others believe that the FDA should make it easier to obtain a bivalent Covid-19 booster.

"One of the disappointments with the mRNA vaccinations is that they aren't holding up as well we'd like for reasons I don't think we fully understand," said Dr. Peter Hotez of the National School of Tropical Medicine at Baylor College of Medicine in Houston.

Hotez stated, "But that is the reality. And as long as that's still the reality, and so long as Covid's around, I think it's worth advocating for it." He also said that he would like to see shots available to adults over 50, not just the 65-and-older group that the FDA is reportedly looking at.

"The doses are there and if they aren't used soon, they will have to be thrown away." Hotez said, "So I believe the FDA and CDC are going to say something soon." This is my guess. There's enough information in the public domain to believe that they'll soon have something to say.

Others are concerned that offering immunocompromised and elderly people more protection might give them a false sense security, but not enough protection.

Due to the fact that vaccines are less effective as we age and because people with weakened immune systems don't see significant protection increases after vaccinations, Stanford University professor Dr. Yvonne Maldonado wonders what a change in policy might do.

"In that situation I just don’t know if additional boosters will make a difference because we know that for many of them, their immune response is not going to to be great," she stated.

She says that Covid-19 has not settled into a predictable pattern that would allow health officials to know if they are giving the right doses.

"If this were a seasonal disease, I would say that we would all be fine because it would only appear once a year. But, we haven't established a pattern of virus circulation. It is risky to wait for a fall booster in the next few months, Maldonado stated.