Obesity can weaken the protection of the vaccine; Unvaccinated Omicron patients face risk of variants

By Nancy Lapid

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 They include research that warrants further study to corroborate the findings and that has not yet been certified by peer review.

Obesity may weaken vaccine protection in the never infected

Severe obesity may weaken the effectiveness of COVID-19 vaccines in those who have never been infected with the coronavirus, according to a small Turkish study.

Among those in the study without prior SARS-CoV-2 infection who had received the Pfizer/BioNTech vaccine, severely obese patients had antibody levels more than three times lower than normal-weight individuals. Among Sinovac Biotech’s CoronaVac recipients, those with severe obesity and no history of prior infection had antibody levels 27 times lower than people of normal weight, according to data presented this week at the European Congress on Obesity in Maastricht, the Netherlands. Low. By comparison, in the 70 volunteers with a previous coronavirus infection, antibody levels were similar in people with and without severe obesity.

For the study, the researchers compared the immune responses to the vaccines in 124 volunteers with severe obesity, defined as a body mass index of 40 or more, and 166 normal-weight individuals (BMI less than 25). In all, 130 participants had received two doses of Pfizer/BioNTech’s mRNA vaccine and 160 had received two doses of Sinovac’s inactivated virus vaccine.

While two doses of the Pfizer/BioNTech vaccine “can elicit significantly more antibodies than CoronaVac in people with severe obesity… more research is needed to determine if these higher levels of antibodies provide greater protection against COVID-19,” said study leader Volkan Demirhan Yumuk. of Istanbul University said in a statement

Unvaccinated Omicron patients at risk of variants

Infection with the Omicron variant of the coronavirus can significantly enhance the immune system’s ability to protect against other variants, but only in people who have been vaccinated, South African researchers have found.

In unvaccinated people, an Omicron infection provides only “limited” protection against reinfection, they reported Friday in Nature. In 39 patients who had Omicron infections, including 15 who had been immunized with vaccines from Pfizer/BioNTech or Johnson & Johnson, the researchers measured the ability of immune cells to neutralize not only Omicron but also earlier variants. At an average of 23 days after Omicron symptoms began, unvaccinated patients had 2.2 times less neutralization of the first version of the Omicron variant compared to vaccinated people, 4.8 times less neutralization of the second sublineage of Omicron, a 12-fold lower Delta neutralization, 9.6-fold lower Neutralization of the Beta variant, and 17.9-fold lower neutralization of the parent SARS-CoV-2 strain. The gap in immunity between vaccinated and unvaccinated individuals “is concerning,” the researchers said.

“Especially as immunity declines, unvaccinated individuals following Omicron infection are likely to have poor cross-protection against existing and possibly emerging SARS-CoV-2 variants,” they said. “The implication may be that Omicron infection alone is not sufficient for protection and vaccination should be given even in areas with high prevalence of Omicron infection to protect against other variants.”

Different vaccines protect well against severe COVID-19

While Pfizer/BioNTech and Moderna’s mRNA vaccines generate higher levels of antibodies to protect against SARS-CoV-2 infection, AstraZeneca’s viral vector-based vaccine provides equivalent protection against hospitalization and death from COVID -19, according to a review of dozens of studies. .

A panel of experts in Southeast Asia reviewed 79 previous studies for a study funded by AstraZeneca. Both types of vaccines were more than 90% effective against hospitalization and death, the panelists said in a report published in Research Square ahead of peer review. “The high level of antibodies formed after vaccination against COVID-19 is often interpreted as the effectiveness of a vaccine. We now understand that while the initial levels of antibody response may vary between vaccines, their ability to avoiding hospitalization or death from COVID-19 is equivalent,” panel member Dr. Erlina Burhan, a lung disease specialist at the University of Indonesia, said in a statement.

A spokesperson for the panelists said the findings suggest that decision-makers should use whatever type of vaccine is accessible and optimal for their local situation, and that people who have a choice of vaccine should know which one they can get faster is better.

A separate study published in Nature Communications found that while Moderna’s mRNA injections provide slightly greater protection against coronavirus infection than the Pfizer/BioNTech vaccine, “there is no difference in the effectiveness of the vaccine in protecting against hospitalization, ICU admission, or death/hospice transfer.

Click to view a graphic from Reuters https://tmsnrt.rs/3c7R3Bl on vaccines in development.

(Reporting by Nancy Lapid; Editing by Bill Berkrot)

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