mRNA vaccines trigger a rescue immune response; some cancer medications can help

August 25 (Reuters) – Here is a summary of some recent studies on COVID-19. They include research that warrants further study to corroborate the results and that has not yet been certified by peer review.

Antibodies decrease but other immune defenses remain vigilant

A new study could help explain why mRNA vaccines from Pfizer / BioNTech and Moderna are more effective at preventing hospitalizations and death than at preventing infections. Test-tube experiments on blood samples from 61 fully vaccinated adults showed that after six months the vaccine-induced antibodies that can immediately neutralize the virus had decreased. But so-called memory B cells, which produce new antibodies if they encounter the virus later, have grown and become better at recognizing viral variants, according to a report released Monday on bioRxiv ahead of peer review. “Your immune system has a backup,” said study leader John Wherry of the University of Pennsylvania’s Perelman School of Medicine. It may take a few days for B cells to start producing antibodies, but these memory B cells “kick in and prevent serious illness,” Wherry added.

First data supports certain cancer treatments during pandemic

Some anti-cancer drugs may help protect patients with malignant tumors from infection with the novel coronavirus, preliminary data suggests. The drugs, known as mTOR / PI3K inhibitors and antimetabolites, target the parts of cells that the virus uses to enter and make copies of itself, including a ‘gateway’ protein on the surface of the cells. cells called angiotensin-converting enzyme 2 (ACE2). The study of 1,701 cancer patients found that after accounting for underlying risk factors, patients treated with mTOR / PI3K inhibitors or ACE2-lowering antimetabolites were 47% less likely to ‘test positive for the virus than patients who have received other drug treatments. Eli Lilly’s Gemzar (gemcitabine) appeared to be particularly promising, according to the report published Thursday in JAMA Oncology. The study does not prove, however, that the drugs reduced infection rates, and much more research is needed to confirm their potential to protect cancer patients against the coronavirus.

One in four vaccinated LA residents contracted COVID

From May to July 2021, as the Delta variant spread, 43,127 residents of Los Angeles County, California were diagnosed with SARS-CoV-2 infections. One in four had been fully immunized, although these patients had lower rates of hospitalization (3.2% vs. 7.6%), intensive care (0.5% vs. 1.5%), and needing machines to aid breathing (0.2% vs. 0.5%) than the unvaccinated. patients, public health officials reported in the U.S. Centers for Disease Control and Prevention’s Weekly Morbidity and Mortality Report on Tuesday. During the study period, the prevalence of the Delta variant increased from less than 9% to at least 87%, the authors note. As of July 25, hospitalization rates were 29 times higher for unvaccinated patients, they estimated, “indicating that COVID-19 vaccination protects against severe COVID-19 in areas with increasing prevalence of the SARS variant -CoV-2 Delta “.

Click for a Reuters graphic on vaccines in development.

Reporting by Nancy Lapid; Editing by Tiffany Wu

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