Children with mild COVID-19 may not develop antibodies; Oral vaccine booster shows promise in monkey study

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Parents walk with children to school amid the coronavirus disease pandemic (COVID-19) in Brooklyn, New York, United States on October 4, 2021. REUTERS / Brendan McDermid

October 20 (Reuters) – The following is a summary of some recent studies on COVID-19. They include research that warrants further study to corroborate the results and that has not yet been certified by peer review.

Children with mild COVID-19 may later lack antibodies

Children who contract a mild case of COVID-19 may not develop antibodies to the virus afterwards, an Australian study suggests. The researchers compared 57 children and 51 adults with mild or asymptomatic COVID-19 infections. Only 37% of children appeared to develop antibodies, compared to 76% of adults – although viral loads were similar in the two groups, the researchers found. Children’s bodies also did not appear to produce second-line cellular immune responses to the virus in the same way adults do, said study leader Paul Licciardi of the Murdoch Children’s Research Institute in Melbourne. Study participants were all infected in 2020, his team reported Monday on medRxiv ahead of the peer review. “Whether this also happens for the current circulating variant (Delta) requires further investigation, as well as studies to understand why children are less likely to produce antibody responses after infection with SARS-CoV-2,” a declared Licciardi. “It is not known if this means children are likely to be re-infected.”

Experimental COVID-19 oral vaccine shows promise in monkeys

COVID-19 booster vaccine that can be given orally to people who already have antibodies from a previous vaccination or infection has shown promising results in monkeys and is expected to be tested in humans soon , depending on the company that develops it. The oral booster uses traditional vaccine technology in which a harmless carrier virus delivers coronavirus proteins into cells on the surface of the tongue, or the lining of the cheeks and throat, stimulating the production of antibodies that can block the disease. virus before it takes hold in the body, said Dr. Stephen Russell, general manager of Vyriad in Rochester, Minnesota, who led the study. “Not only would an oral COVID-19 vaccine be more practical and acceptable … but it could also lead to better immunity because it is administered at the site where the COVID-19 virus typically enters the body,” he added. . In monkeys one week after vaccination, antibody levels increased almost 100-fold, with no side effects, Russell said. A study report released Monday on bioRxiv ahead of peer review says Vyriad is working with the U.S. Food and Drug Administration to schedule human trials.

Plants can be useful in vaccine production

The plants could one day be used to produce COVID-19 vaccines, according to researchers developing a nasal spray vaccine. Vaccines work by delivering antigens, which are replicas of pieces of virus or bacteria that train the immune system to recognize and defend against the invader. Vaccine antigens are typically produced in mammalian cells, but previous studies have suggested that their production in tobacco-related Nicotiana benthamiana plants would be cheaper and safer. In the current lab study, published Monday on bioRxiv ahead of peer review, antibodies from COVID-19 survivors recognized and responded to coronavirus antigen produced in plants “in the same way they recognize a standard antigen produced in mammalian cells “. said study leader Allyson MacLean from the University of Ottawa. The intranasal vaccine is not intended to replace conventional (injected) vaccines, but rather to add another layer of protection by boosting the protection of the immune system in the respiratory tract, where the virus first attaches, ”he said. MacLean said. spray used to boost immune protection when traveling or attending events with large numbers of people. “

Click for a Reuters graphic on vaccines in development.

Reporting by Nancy Lapid; Editing by Bill Berkrot

Our Standards: Thomson Reuters Trust Principles.


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