Johnson & Johnson vaccine is 66% effective in preventing Covid-19

The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for Covid-19, the illness caused by the virus.

Johnson & Johnson vaccine 66% effective in a global trial

Johnson & Johnson's single-dose vaccine was 66% effective in preventing moderate and severe Covid-19 in a late-stage global trial with nearly 44,000 volunteers that includes regions with worrisome variants of the virus, the company said on Friday.

Protection levels 28 days after vaccination varied from 72% in the United States to 66% in Latin America and just 57% in South Africa, where a potent new variant has become prevalent.

Two-dose vaccines from Pfizer/BioNTech and Moderna were around 95% effective in pivotal trials. But those were conducted before the highly transmissible new variants emerged.

"Right now, any protection and additional vaccine is great," said Walid Gellad, a health policy associate professor at the University of Pittsburgh who was not involved in the trial.

"The key is not only overall efficacy but specifically efficacy against severe disease, hospitalization, and death."

South African virus variant may resist antibody drugs

In a news release, J&J said its vaccine was 85% effective in stopping severe disease and preventing hospitalisation across all geographies and against multiple variants. The vaccine uses a common cold virus to introduce coronavirus proteins into cells and trigger an immune response. The company plans to seek emergency use authorization from the US Food and Drug Administration next week.

High antibody levels seen in newborns of Covid-19 survivors

A mother's Covid-19 antibodies can cross the placenta, potentially protecting her fetus from infection, researchers reported on Friday in JAMA Pediatrics. Several weeks after the mother's infection begins, antibody levels in umbilical cord blood "can be as high as - or even higher - than the levels in maternal blood," said study leaders Dr Karen Puopolo and Dr Scott Hensley of the University of Pennsylvania. In their study, out of 83 women who had Covid-19 antibodies when they gave birth, 72 of their newborns also had antibodies but no evidence of direct infection.

"It is reassuring that maternal infection, whether symptomatic or asymptomatic, results in sufficient antibody production for an efficient transplacental antibody transfer to newborns of infected mothers," said Dr Flor Munoz of Baylor College of Medicine in an editorial published with the study. It is possible antibodies created via a vaccine could have the same effect, Munoz noted.

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Transfer of substances in the mother's blood to the fetus starts around 17 weeks of gestation, she said, which suggests that "maternal vaccination starting in the early second trimester ... might be optimal to achieve the highest levels of antibodies in the newborn."

Skin problems can persist after Covid-19

Add bothersome skin conditions to the list of symptoms that can follow infection with the new coronavirus, a new report warns. Between April and October, an international registry established by dermatologists received reports of roughly 1,000 Covid-19 patients with itchy welts, rashes, scaly plaques, or pernio, an inflammation of the fingers and toes upon exposure to cold. In half of the cases, the skin problems lasted more than two weeks.

That was more often true for patients with scaly plaques and pernio. Given that some of the patients had only mild Covid-19, the data suggest that inflammation from the disease may persist even among those who were not seriously ill, researchers said in The Lancet Infectious Diseases.

"Since the onset of the Covid-19pandemic, appreciation for persistent morbidity beyond the acute phase of the disease has increased," they said. "To our knowledge, our data represent the largest dataset to date on persistent skin signs and symptoms of Covid-19."