The following is a summary of some recent studies on COVID-19. These include studies that require further study to confirm findings and that have not yet been certified by peer review.
Obesity can weaken the protection of the vaccine in those who have never been infected
According to a small Turkish study, severe obesity may impair the effectiveness of COVID-19 vaccines in those who have never been infected with the coronavirus.
Among study participants without a previous SARS-CoV-2 infection who received the Pfizer (PFE.N) / BioNTech vaccine, severely obese patients had more than three times lower levels of antibodies than normal-weight people. According to data presented this week at the European Congress on Obesity in Maastricht, the Netherlands, among recipients of CoronaVac Sinovac Biotech (SVA.O) in those who are severely obese and had no history of infection, antibody levels were 27 times lower than in normal weight people. . For comparison, in 70 volunteers with previous coronavirus infection, antibody levels were the same in people with severe obesity and without it.
For the study, researchers compared immune responses to vaccines in 124 severely obese volunteers, defined as a body mass index of 40 and above, and 166 people with normal body weight (BMI less than 25). A total of 130 participants received two doses of Pfizer / BioNTech mRNA vaccine and 160 received two doses of Sinovac virus vaccine.
While two doses of Pfizer / BioNTech “may generate significantly more antibodies than CoronaVac, people with severe obesity need more research to determine whether these higher levels of antibodies provide greater protection against COVID-19.” said Volkan study leader Demirkhan Yumuk of Istanbul. The university said in a statement
Unvaccinated Omicron patients are at risk for options
South African researchers have found that infection with the Omicron coronavirus variant can significantly improve the immune system’s ability to defend itself against other variants, but only in people who have been vaccinated.
In unvaccinated people, Omicron infection provides only “limited” protection against re-infection, Nature reported on Friday. In 39 patients who had Omicron infections – including 15 who were immunized with Pfizer / BioNTech or Johnson & Johnson (JNJ.N) vaccines – the researchers measured the ability of immune cells to neutralize not only Omicron but also earlier variants. On average, 23 days after the onset of Omicron symptoms, unvaccinated patients had 2.2 times less neutralization of the first version of the Omicron variant compared to vaccinated humans, 4.8 times less neutralization of the second Omicron subline, and 12 times less neutralization of Delta. , 6 times less neutralization of the beta variant and 17.9 times less neutralization of the original SARS-CoV-2 strain. The gap in immunity between unvaccinated and vaccinated individuals is “a cause for concern,” the researchers said.
“Especially as immunity declines, unvaccinated people after Omicron infection are likely to have weak cross-protection against existing and possibly new variants of SARS-CoV-2,” they said. “Perhaps this means that one Omicron infection is not enough to protect against, and vaccination should be carried out even in areas with a high prevalence of Omicron infection to protect against other options.”
Various vaccines protect well against the severe form of COVID-19
While mRNA vaccines from Pfizer / BioNTech and Moderna (MRNA.O) generate higher levels of antibodies to protect against SARS-CoV-2 infection, the AstraZeneca (AZN.L) vaccine based on viral vectors provides equivalent protection against hospitalization and death from COVID-19, according to a review of dozens of studies.
A group of experts in Southeast Asia reviewed 79 preliminary studies for a study funded by AstraZeneca. Both types of vaccines have shown more than 90% efficacy against hospitalization and death, participants in the discussion said in a report posted on Research Square before the peer review. “The high levels of antibodies produced after vaccination against COVID-19 are often interpreted as vaccine efficacy. We now understand that while baseline antibody responses may vary with vaccines, their ability to prevent hospitalization or death from COVID-19 is equivalent, ”said team member Dr. Erlina Burhan, a lung specialist at the University of Indonesia. . .
A spokesman for the discussion said the results showed that decision-makers should use any type of vaccine that is available and optimal for their local situation, and that people who have a vaccine choice should know what they are can probably get the best.
A separate study published in Nature Communications found that while Moderna mRNA injections provide slightly greater protection against coronavirus infection than the Pfizer / BioNTech vaccine, “there are no differences in vaccine efficacy for protection against hospitalization, admission / resuscitation or death. to the hospice. “