COVID-19 roundup: Obesity weakens vaccine protection, changing risks

COVID-19 roundup: Obesity weakens vaccine protection, changing risks

In this week’s report, the latest scientific research on the coronavirus, including treatments and vaccines, suggests that obesity may impair vaccine protection in those who have not had COVID-19, unimmunized Omicron patients may be at risk for variants, and different vaccines protect well. Against severe infections.

Obesity weakens those who have never been infected

A small Turkish study shows that obesity may impair the effectiveness of COVID-19 vaccines in those who have never had the coronavirus.

Among those who participated in the study without prior SARS-CoV-2 infection and who received the Pfizer/BioNTech vaccine, obese patients had antibody levels three times lower than individuals of normal weight.

Among the CoronaVac recipients from Sinovac Biotech, those who were obese with no history of previous 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. .

By comparison, in the 70 volunteers who had previously contracted coronavirus, antibody levels were similar in obese and non-obese people.

For the study, researchers compared the immune responses to vaccines in 124 obese volunteers — defined as a BMI of 40 or higher — and 166 normal-weight individuals (BMI less than 25). Overall, 130 participants received two doses of the Pfizer/BioNTech mRNA vaccine and 160 participants received two doses of the inactivated virus vaccine from Sinovac.

While two doses of the Pfizer/BioNTech vaccine “may generate significantly more antibodies than CoronaVac in obese people…More research is needed to determine whether these higher antibody levels provide greater protection against COVID-19.” Study leader Volkan Demirhan Yumuk of Istanbul University said in a statement

Unvaccinated Omicron patients

South African researchers have found that infection with the omicron variant of the coronavirus can significantly improve the immune system’s ability to protect against other variants, but only in vaccinated people.

They reported Friday in the journal Nature that omicron infection provides “limited” protection from reinfection in unvaccinated people. In 39 patients who developed omicron infection — including 15 who were immunized with vaccines from Pfizer/BioNTech or Johnson & Johnson — the researchers measured the ability of immune cells to neutralize not only the omicron but also its precursor variants.

On average 23 days after the onset of omicron symptoms, unvaccinated patients had 2.2 times lower neutralization of the first copy of the omicron variant compared to vaccinated subjects, 4.8 times lower neutralization of the second omicron subseries, and 12 times lower neutralization, 9.6 times lower neutralization Lower beta variant, 17.9-fold lower neutralization of the original SARS-CoV-2 strain.

The researchers said the gap in immunity between unvaccinated and vaccinated individuals was “alarming”.

“Especially with diminished immunity, it is likely that non-immunized individuals following omicron infection may have poor cross-protection against current and possibly emerging variants of SARS-CoV-2,” they said.

“The implication may be that omicron infection alone is not sufficient for protection and vaccination should be given even in areas where omicron infection is common to protect against other variants.”

Different vaccines protect well

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

A panel of Southeast Asian experts reviewed 79 previous studies of an AstraZeneca-funded study. In a report published on Research Square ahead of peer review, panel members said both types of vaccines have shown more than 90% effectiveness against hospitalization and death.

“The high level of antibodies formed after a COVID-19 vaccine is often interpreted as a vaccine’s efficacy. We now understand that although levels of initial antibody response can vary for different vaccines, their ability to prevent hospitalization or death due to COVID-19 is the equivalent,” panel member Dr. Erlena Burhan, a pulmonologist at the University of Indonesia, said in a statement.

A spokesperson for panel members said the findings suggested decision makers should use whichever type of vaccine is accessible and ideal for their local situation, and that people with a vaccine choice should know that the vaccine they can get the fastest is best.

A separate study published in Nature Communications found that while Moderna’s mRNA shots offered slightly greater protection against coronavirus infection than the Pfizer/BioNTech vaccine, “there are no differences in vaccine efficacy to protect against hospitalization, ICU admission, or death/reproduction transfer.” .

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2022-05-08 11:24:00

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