The revised Moderna vaccine is more effective against Omicron, studies suggest

modern Provisional results announced on Wednesday We call the latest coronavirus vaccine targeting the Omicron mutant “our key candidate” to act as a booster shot in the United States in the fall.

The company’s researchers tested booster doses that combined the original vaccine with a vaccine that specifically targeted the mutant Omicron, which prevailed last winter. They found that, in the absence of previous evidence of coronavirus infection, this combination produced 1.75-fold levels of neutralizing antibodies to Omicron compared to the existing Coronavirus vaccine alone.

While these results seem encouraging to their faces, many experts are worried that the virus is evolving so fast that it outperforms its ability to change vaccines. At least as long as the United States relies on human clinical trials for results.

Moderna’s new findings from a clinical trial of 814 volunteers show that one month after being given a booster shot, the updated vaccine has a significantly stronger immune response to Omicron than existing vaccines. It shows that it has been brought. Booster shots followed the previous three doses of Moderna’s vaccine.

However, Omicron has been producing subvariants for months. Some vaccine experts say it is important how well the new booster formulation can protect against the latest subvariants BA.4 and BA.5, not Omicron itself.These two subvariants were first detected in South Africa earlier this year. Currently accounts for 13% of new cases in the United States And it is spreading rapidly.According to some estimates, within a month they will The other two Omicron subvariants BA.2 When BA.2.12.1Currently dominant.

Moderna did not release data on how the updated vaccine worked against BA.4 or BA.5. In a presentation Wednesday morning, the company’s president, Dr. Stephen Hogue, said researchers are still collecting data on them and other subvariants.

However, he found that from very small samples and other isolated studies, the levels of neutralizing antibodies caused by the updated vaccine were against BA.4 and BA.5 subvariants compared to Omicron. He said it suggests that it is 2-3 times lower.

Also, Moderna researchers cannot yet say whether the reconstituted vaccine provides more lasting protection than existing vaccines.

The latest subvariants appear to spread even faster than previous versions of Omicron and may be better at dodging immune system defenses. It is unclear if they cause more serious illness. Dr. Anthony S. Forch, White House Chief Medical Advisor, said in an interview Tuesday: South Africa where BA.4 and BA.5 are widespread“Although hospitalizations have increased slightly, ICU utilization and mortality remain stable and low in practice.”

In any case, given the speed of virus mutation, it makes sense for some vaccine experts to target the latest version rather than the form of the virus that has already been or will soon be overtaken. Some say it’s true.

The problem is that Moderna and Pfizer, other major US coronavirus vaccine makers, will conduct more human clinical trials and still produce shots by the fall, which the Biden administration wants to be able to do. I don’t have enough time. We provide the latest vaccines to counter the expectations of public health experts for a winter surge.

As a result, regulators may be forced to choose the latest vaccines based on data from laboratory tests and tests in mice and other animals rather than strong human tests. .. By the fall, new variants or subvariants of concern may emerge.

The Food and Drug Administration’s external advisor Scheduled to meet on June 28th Discuss which vaccines are most effective as fall boosters.Vaccine makers They said they needed to start production immediately..

“Of course, the final decision is always left to the FDA,” said Dr. Fauci. “But what the FDA is likely to do is keep burning as much iron as possible, and they return to an alternative path of decision, laboratory data and possible animal data. You may need to. “

Asked if Americans would accept booster formulations without long human trials, he said, “People who are really very worried about protecting themselves will.”

John Moore, a virologist at Weill Cornell Medicine in New York, said at this point in the pandemic he would be comfortable switching to another model of coronavirus vaccine development, such as the model used to change the flu vaccine each year. I did. ..

“We’re going to get new variants and make new vaccines, but we don’t have to require all animal and human testing,” he said. But “it will require significant policy changes by the FDA,” he added. “It’s hard to say whether the public will accept it.”

Trial of Moderna, a vaccine targeting Omicron, began in late February. The average age of the participants was 57 years. All volunteers were vaccinated with Moderna’s existing vaccine three times, two times, and then boosted an average of eight months after the second.

Approximately four and a half months after the first booster, 377 volunteers received a second booster with an existing vaccine, and 437 received a booster designed to work against Omicron. The updated booster produced a stronger immune response between those who were previously infected and those who were not.

Overall, people with updated boosters had 59% higher levels of neutralizing antibodies than those with existing boosters, according to data released by Moderna. Antibodies are the body’s first line of defense to prevent infection by the coronavirus. No other immune response was measured to protect against Covid-19 disease. These tests are much more complex and time consuming.

Dr. Paul Burton, Moderna’s Chief Medical Officer, said the results are very promising. “I really feel that this is a kind of fundamental turning point in the fight against this virus, which means it can adapt to variants,” he said. “I can do it.”

However, Dr. Moore said that less than double the increase in neutralizing antibodies compared to existing vaccines is “a small benefit.”

“Given the cost and logistics, and everything else involved, does that justify the switch of vaccine composition?” He asked. “That’s the subject of debate.”

Pfizer and its German partner BioNTech are also testing Omicron-specific vaccines and will announce the results shortly.

April, modern Announcement of provisional results About a vaccine modified to attack the beta variant that was first detected in late 2020. The company said the combination provides strong protection against delta and omicron variants as well as beta. However, officials said they hoped that the Omicron-specific vaccine would be a better candidate.