Moderna said redesigned COVID-19 vaccines will better protect against new variants

The US laboratory Moderna announced through its website that it expects to offer updated reinforcements of its vaccine by autumn against COVID-19, which combines the original vaccine with protection against the Ómicron variant.

Current COVID-19 vaccines are based on the original version of the coronavirus. But the virus continues to mutate, and the highly contagious Ómicron variant — and its subvariants — represent the most recent threat. Before Ómicron emerged, Moderna was studying a combination vaccine that added protection against a previous variant called Beta.

On Tuesday, the drug company said that people who received the Beta vaccine combination produced more antibodies capable of fighting various variants, including Ómicron, than the current regular booster vaccines. The pharmaceutical company is working, he said, on another version of the vaccine and estimated that it may be ready between May and June next.

Moderna published her study, conducted by scientists from the organization itself and still without external evaluation, in Research Square. The pharmaceutical giant estimates that, when the autumn boreal arrives, it will be able to offer a better version of its messenger RNA vaccine, as experts estimate that it is very likely that the coronavirus will re-emerge with a large number of cases. The study was not intended to evaluate the effectiveness of the vaccine; it only measured the immune system response, which may indicate efficacy.

As reported by The New York Times, Moderna, other pharmaceutical companies, and the U.S. National Institutes of Health (NIH) are working at full pace to redesign available COVID-19 vaccines for manufacturing during the northern hemisphere summer in order to reach in time to start applying them with the first cold of autumn. Moderna is the first laboratory to publish its preliminary studies which, he said, are proving successful.

As both in-house and independent studies have reported, both the Moderna and Pfizer/BioNTech vaccines, both with the mRNA platform and developed for the first of the SARS-CoV-2 strains emerged at the end of 2019, continue to be effective in preventing hospitalizations and deaths. It has also been found that the protection it provides is decreasing rapidly, so in many countries reinforcements have already been authorized, at least for people over 50 years of age and people with underlying diseases that place them within the risk groups.

Moderna, in her publication, pointed out that studies showed that it is possible to design a bivalent vaccine specifically targeted for two of the variants, but that it can be effective for other strains. According to the report, researchers at the laboratory combined the existing vaccine against the original strain with one specially prepared to combat the Beta variant, first detected in late 2020. The combination of both, they said, showed a stronger defense both for the mutations for which it was targeted and for Delta and Ómicron.

People who participated in the study who received a booster dose of the redesigned vaccine produced more than twice the level of antibodies to the Ómicron variant compared to those who received a booster dose of the existing Moderna vaccine. T he improvement was also manifested in the duration of protection, since it persisted for six months against Ómicron, although it fell against Delta essentially at the same level as that caused by the original vaccine.

Although the Beta variant emerged early, about a year after the original one from Wuhan, the laboratory considered it relevant to this study because it contains several mutations that “have been persistent in more recent variants of concern, including Omicron”. Beta has no longer been circulating for several months.

Dr. Paul Burton, Moderna's chief medical officer, said in an interview that his team was betting on even better results by combining the existing vaccine with one aimed at Ómicron. It is producing a number of subvariants, including BA.1 and BA.2, and many experts suggest that it is probably the best target for a new vaccine.

“I think we should assume that (Ómicron) will continue to be an important player even in the fall,” said Dr. Burton, considering the evolving capacity that variant is demonstrating.

The study carried out by the laboratory measured the levels of antibodies generated by the volunteers, that is, the body's first line of defense to avoid infection. On the other hand, it has not yet measured other immune responses that also defend against the disease. These tests are much more complex and costly to perform.

Even though measuring antibodies only allows us to have a partial picture of the immune response generated by the vaccine, “we still think that keeping antibody levels high is important,” said Dr. John Beigel, director of clinical research who oversees vaccine trials of NIH, mentioned The New York Times.

Studies to verify the effectiveness of the updated vaccine require small clinical trials combined with laboratory tests. First, the inoculants are originally designed to attack one variant alone or combined with another. A small group of volunteers receive the redesigned formulation. Scientists analyze the blood samples of these people in the laboratory to neutralize antibodies against the entire range of variants and only one or two for which it was made.

The antibodies observed in the group of volunteers were broken down at different rates, depending on the variant. “That's why we need six-month data, ideally, to evaluate how well any updated vaccine would work,” Dr. Beigel explained.

Some scientists believe that a protein-based inoculant, possibly such as that developed by Sanofi and GSK, could act better as a reinforcement than the new versions of Moderna or Pfizer-BioNTech formulations. The latter were used to vaccinate some 250 million Americans.

But Burton called Moderna's results with its bivalent beta vaccine “very reassuring” in terms of both safety and immune response. He said that the laboratory is looking forward to obtaining results by June of its bivalent vaccine aimed at the Ómicron variant.

In this regard, Stéphane Bancel, executive director of Moderna, had also said: The vaccine “remains our main candidate” for a booster this fall,” he said.

If a bivalent vaccine targeting the Beta variant works well against Omicron, Burton added, one that targets Ómicron directly would presumably work even better. He also stressed that he expects the new study to show high and long-lasting levels of antibodies against Delta and Ómicron. “It's worth waiting for those two months,” he said. In the United States, it is estimated that health authorities will approve a booster vaccine once a year.

As for the doses applied to the approximately 900 volunteers in the bivalent beta trial, it was reported that one third received a 50 microgram dose of the updated vaccine, the same dose now authorized for a booster injection of the existing vaccine. The rest received a dose of 100 micrograms. Volunteers suffered fewer side effects with the weakest dose. Burton said the company would probably decide on that dose.

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