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

By Nancy Lapid

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

Obesity can weaken vaccine protection in those who have never been infected

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

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

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

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

Omicron patients not vaccinated at risk of variants

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

In unvaccinated people, an Omicron infection only provides “limited” protection against reinfection, Nature reported Friday. In 39 patients who had Omicron infections, including 15 who had been immunized with Pfizer / BioNTech or Johnson & Johnson vaccines, the researchers measured the ability of the immune cells to neutralize not only Omicron but also previous variants. At an average of 23 days after the onset of Omicron symptoms, unvaccinated patients had 2.2 times less neutralization than the first version of the Omicron variant compared to vaccinated individuals, a neutralization 4, 8 times lower than the second underline of Omicron, a Delta neutralization 12 times lower, Neutralization of the beta variant 9.6 times lower and neutralization 17.9 times lower than the original strain SARS-CoV-2. The gap in immunity between unvaccinated and vaccinated individuals “is worrisome,” the researchers said.

“Especially as immunity decreases, people who are not vaccinated after 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 a high prevalence of Omicron infection to protect against others. variants “.

Different vaccines protect well against severe COVID-19

While Pfizer / BioNTech and Moderna 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 by COVID-19, according to a review of dozens of studies. .

A group of Southeast Asian experts reviewed 79 previous studies for a study funded by AstraZeneca. Both types of vaccines showed more than 90% effectiveness against hospitalization and death, panelists said in a report published in Research Square ahead of the 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. “Her ability to avoid being hospitalized or dying from COVID-19 is equivalent,” said panelist Dr. Erlina Burhan, a specialist in lung disease at the University of Indonesia, in a statement.

A spokesman for the panelists said the findings suggest that decision-makers should use any vaccine that is accessible and optimal for their local situation, and that people with a vaccine option should know that which they can get faster is the best.

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

Click to view a Reuters chart https://tmsnrt.rs/3c7R3Bl on developing vaccines.

(Reporting by Nancy Lapid; Editing by Bill Berkrot)

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