The following is a summary of some recent studies on COVID-19. They include research that qualifies for further studies to confirm the results and which has not yet been certified by peer review.
Delta variant does not seem to make children sicker
The Delta variant of coronavirus does not appear to cause more serious illness in children than previous forms of the virus, a British study suggests.
Earlier this year, the research team found that the Alpha variant of the virus did not appear to make children sicker than the so-called wild or original form of the virus first seen in China. New data suggests that children also do not get sicker from Delta than they did from Alpha.
Researchers compared two groups of school-age children with COVID-19: 694 infected with the Alpha variant between late December 2020 and early May 2021 and 706 infected with Delta between late May and early July .
As reported Thursday on medRxiv prior to peer review, children infected with Delta had slightly more symptoms. However, in both groups, very few children had to be hospitalized, and long periods of illness were uncommon.
In both groups, half of the children were ill for a maximum of five days. The researchers lacked information on differences between the groups that could have influenced the results, e.g. About lockdown barriers were in place and the effects of different seasons.
“Our data suggest that the clinical characteristics of COVID-19 due to the Delta variant in children are broadly similar to COVID-19 due to other variants,” the researchers concluded.
This appears to be in line with data reported by the US Centers for Disease Control and Prevention (CDC).
“Although we see more cases in children … these studies showed that there was no increased disease rate in children,” said CDC Director Dr. Rochelle Walensky on the delta-driven wave in a statement.
“More children have COVID-19 because there is more disease in society.”
Secondary immune response stronger after infection than vaccination
In COVID-19 survivors, important components of the body’s immune response, called memory B cells, continue to develop and become stronger for at least several months, producing highly potent antibodies that can neutralize new variants of the virus, a new study has found.
By comparison, vaccine-induced memory B cells are less robust, develop only in a few weeks, and never “learn” to protect against variants, researchers reported in a paper published Thursday in Nature.
COVID-19 vaccines produce more antibodies than the immune system does after a coronavirus infection. But the immune system’s response to infection seems to surpass its response to vaccines when it comes to memory B cells.
Whether antibodies are induced by infection or vaccine, their level drops within six months in many people. But memory B cells are ready to produce new antibodies if the body encounters the virus. Prior to this study, there had been little data on how vaccine-induced B cells can be compared to infection-induced B cells.
The researchers warn that the benefits of stronger B-memory cells after infection do not outweigh the risks associated with COVID-19.
“While a natural infection can cause the maturation of antibodies with a broader activity than a vaccine does, a natural infection can also kill you,” said study leader Michel Nussenzweig of Rockefeller University in a statement.
“A vaccine will not do that and actually protects against the risk of serious illness or death as a result of infection.”