Friday, October 15, 2021

New UCSF study: Vaccine-resistant viruses driving ‘breakthrough’ COVID infections

The “success” among vaccinated people is known for a disturbing surge in COVID-19 cases with weakened immunity and the brutal contagion.

But a new UC San Francisco Analysis A third of the Bay Area’s 1,373 cases reveal a more ominous, problem: the coronavirus is learning to outperform our immune systems.

According to research by leading virologist Dr. Charles Chiu, variants with antibody-resistant mutations are playing a big role in the epidemic in our highly vaccinated region.

His team found that 78% of infections in fully vaccinated people between studies were caused by variants with these mutations, while 48% of cases were infections in non-vaccinated people, Which remained easy targets for previous generations of viruses. Overall, the proportion of cases linked to these variants more than doubled between February and June.

The findings join a growing list of studies that are uncovering why immunizations are still susceptible to infection – and provide a deeper understanding of what we may face in the future.

The study confirms that vaccinated people are still more protected from serious illness, hospitalization, and death.

“But I worry that as long as the virus is circulating, it will continue to mutate and evolve, which in turn will keep it spreading,” he said.

The study suggests that new iterations of the virus will likely become even more resistant over time, “unless, you see, the vaccine isn’t working, or its efficacy will drop significantly,” he said.

He said that our vaccines will not suddenly go to waste. So far, it appears to be a gradual process. Resistant variants will gradually dominate over time, he predicted.

Chiu said the rollout of booster vaccines, planned to begin the week of September 20, will help strengthen our defense against these breakthroughs.

But as the virus continues to evolve, he said, vaccines may need to be improved to keep us safe.

The team’s second major finding was more reassuring: People who never developed symptoms during a “breakthrough” infection had much lower levels of the virus — a finding that underscores concerns that people who are vaccinated. Unknowingly fueling the pandemic.

However, people who show symptoms have the same virus levels as infected uninfected people – so they can spread the virus. It confirms a finding first reported weeks ago by a CDC study in Provincetown, Massachusetts.

“You are essentially as contagious as the unvaccinated person,” he said.

The UCSF team performed genome sequencing of viral samples from Bay Area residents who sought treatment for COVID-19 at UCSF hospitals and clinics between February 1 and June 30, as well as people who had The infection was detected at community testing sites. Of these, 125, or 9.1%, were vaccine “success” cases. The study, published as a preprint Wednesday, has not yet been reviewed or confirmed by other investigators.

Infectious disease specialist Dr. A major concern, said Gary Schulnick, is the study’s observation that people infected with these “escape mutants” can infect others, including by vaccination. not included in the study.

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“The implication of their discovery is that vaccine-resistant mutants of the COVID virus may spread more widely in the population,” he said. “If this happens, it may require the development and use of COVID booster vaccines that specifically target such mutants.”

Overall, three factors are driving the successes, according to Chiu, director of the UCSF-Abbott Viral Diagnostics and Discovery Center and associate director of the UCSF Clinical Microbiology Laboratory.

One is exposed to a large number of viral particles by people infected with the delta type. People infected with Delta can shed about four times more virus than people infected with the original virus. Some of these viruses can slip through our antibody defenses, leading to infection.

According to recent data from Moderna and Pfizer Vaccines, another immunity is declining. Six to nine months after vaccination, our bodies produce less effective antibodies.

The third reason is this new and worrying trend: the transition from a variant with a resilient mutation. The new study found that the proportion of cases caused by these variants increased from 40% to 89% at five months.

The team did not study the effect of the mutation on the effectiveness of the immune system’s second arm, which includes T cells that kill the virus.

Vaccination is not to be blamed for the increase in variants with these mutations, Chiu said. Because we naturally produce antibodies in response to exposure and infection, the virus is constantly changing in order to survive.

“The virus is going to evolve to become antibody resistant, whether you deploy a vaccine or not,” he said. “But because we have a vaccine, there is a way to stop the virus from spreading and developing further.”

One of these mutations, L452R, is built into the genetic code of the dreaded delta variant, which now dominates. But this and other mutations, including E484K and F490S, can be carried by other resistant variants such as beta, gamma, epsilon and lambda. Our antibodies are less effective at fighting off the types that carry these mutations.

These mutations do not render our antibodies useless against the virus. Resistance is almost always partial; It is not an “all or none” attribute.

“This reduction in vaccine efficacy may be minor or significant due to infection by a resistant variant,” he said.

The mutations make it harder for antibodies to bind to the virus, so the virus is able to slip through and infect a cell. More of them are needed to neutralize the virus.

A booster dramatically increases our antibody levels. A new and improved booster targeted to a specific type, like the Delta, could push them even higher.

Ultimately, we will control this epidemic by vaccinating as many people as possible, Chiu said.

Nation World News Deskhttps://nationworldnews.com
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