COVID SCIENCE Antibody protection after mild COVID-19 may not last; about 100 million people had long COVID

By Nancy Lapid

Nov 17 (Reuters) – The following is a summary of some recent studies on COVID-19. They include research that requires further study to confirm the results, and this has yet to be attested by peer review.

Antibody protection against mild COVID-19 may not last

Almost everyone who has had a mild case of COVID-19 still has antibodies against the coronavirus a year later, but that may not protect them from new variants, a small study suggests. Among 43 Australians who treated mild COVID-19 early in the pandemic, 90% still had antibodies 12 months later. But only 51.2% had antibodies that showed “neutralizing action” against the original version of the virus and only 44.2% had antibodies that could neutralize the early Alphan variant, the University of Adelaide’s research team reported on Thursday in medRxiv https://bit.ly/3oGL2k1 before peer review. Neutralizing antibodies against the now dominant and highly transferable Delta variant were seen in only 16.2%, with 11.6% against Gamma, and against Beta in only 4.6%. Those who had mild COVID-19, “are vulnerable to infection with circulating and newly emerging variants of SARS-CoV-2 12 months after recovery,” the researchers said. They said the findings “reinforce the potential advantage” of adapting vaccine accelerations to currently circulating variants, similar to how annual influenza vaccines are adapted to current influenza strains.

100 million have or have had long COVID, study estimates

More than 40% of COVID-19 survivors worldwide have had long-term consequences of the disease, researchers from the University of Michigan estimate, based on their review of 40 earlier studies from 17 countries that looked at patient experiences with so-called long-term. COVID, defined as new or persistent symptoms four or more weeks after infection. The prevalence rises to 57% among survivors who required hospitalization, the researchers reported Tuesday in medRxiv https://bit.ly/3FmiuTu ahead of a peer review. The rate was 49% among female survivors and 37% among males, they said. The estimated long-term COVID rate was 49% in Asia, 44% in Europe and 30% in North America. Among the most common problems, fatigue was estimated to affect 23%, while shortness of breath, joint pain and memory problems each affected 13%. The study probably did not capture all cases of long-term COVID, the researchers say. “Based on a WHO (World Health Organization) estimate of 237 million COVID-19 infections worldwide, this global combined … estimate indicates that approximately 100 million individuals are currently experiencing or have previously experienced long-term health-related consequences of COVID- 19. ” These health effects, they warn, “can exert considerable stress on the health care system.”

The effect of a virus on blood-thinning molecules causes clots

Dangerous blood clots often seen in patients with COVID-19 occur at least in part because the sting of the virus binds to molecules in the blood that play key roles in preventing clotting, thus inactivating them, new research shows. With the virus attached to them, “these molecules (heparan sulfate / heparin) cannot perform their usual anticoagulant activities,” explained Jingyu Yan of the Dalian Institute of Chemical Physics in China. Blood clots associated with COVID-19 often damage the lungs and other organs and can cause heart attacks and strokes. The excessive coagulation was attributed to the high levels of inflammation caused by the SARS-CoV-2 infection. So far it has not been clear that the virus itself also has a direct effect, Yan’s team reported in the International Journal of Biological Macromolecules https://www.sciencedirect.com/science/article/pii/S0141813021022704. Fortunately, they point out, the now common practice of giving patients with COVID-19 blood-thinning drugs can “significantly reduce” the clotting caused by the virus.

Click for Reuters chart https://tmsnrt.rs/3c7R3Bl on vaccines in development.

(Reporting by Nancy Lapid; Editing by Bill Berkrot)

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