By Nancy Lapid
(Reuters) – The following is a summary of some of the latest scientific studies on the new coronavirus and attempts to find treatments and vaccines for COVID-19, the disease caused by the virus.
COVID-19 after vaccination may be less contagious
People who receive a COVID-19 vaccine can still become infected with the new coronavirus, although they are likely to be protected from serious disease, and a new study suggests they may also be less contagious. At a major Israeli health maintenance organization, where 650,000 members received the two-dose vaccine from Pfizer Inc and BioNTech SE, researchers identified 2,897 patients who later tested positive for COVID-19. The amounts of virus on swabs from the nose and throat were quadrupled for infections occurring at least 12 days after the first dose of vaccine compared to what is typically seen in unvaccinated COVID-19 patients, the Maccabi Health Services research team and the Technion – Israel Institute of Technology found. Viral loads are known to be associated with infectivity and disease severity. But this study was not a randomized trial, and it did not look at patients’ viral loads over time or the rate at which their contacts became infected, which would be the most direct evidence of whether a vaccine could reduce virus transmission. decreases. Still, in a paper posted Monday on the medical website medRxiv ahead of peer review, the authors concluded, “These reduced viral loads indicate lower infectivity, further contributing to the impact of the vaccine on virus spread.” (https://bit.ly/2LK5HnE)
Research shows a range of COVID-19 benefits of the arthritis drug
A large study adds to evidence that tocilizumab, Roche’s arthritis medicine, sold under the brand name Actemra, reduces the risk of death of hospitalized patients with COVID-19, shortens their hospital stay and their need for mechanical ventilation decreases. The randomized trial included more than 4,000 patients with varying degrees of disease. Some only required simple oxygen therapy, while others required mechanical ventilation. Most were also given a steroid such as dexamethasone. The 28-day mortality rate was 29% for patients in the tocilizumab group and 33% in the control group, according to a report posted on the medical website medRxiv Thursday prior to peer review. After taking into account the age, gender and other risk factors of the patients, tocilizumab was associated with a 14% reduction in the risk of death. “We now know that the benefits of tocilizumab extend to all COVID patients with low oxygen levels and significant inflammation,” said co-leader Peter Horby of the University of Oxford in a statement. Used in conjunction with steroids, Horby added, “the impact is significant.” (https://bit.ly/3aUZhuy)
In some COVID-19 patients, bone marrow cells travel to the brain
Very large bone marrow cells appear in the brains of people who died of COVID-19, which researchers say may help explain some of the neurological problems associated with the disease. The cells, called megakaryocytes, are normally located in the bone marrow and make platelets for blood to clot. “We found that in some patients who died of COVID-19, the capillaries – the smallest blood vessels – contained very large cells called megakaryocytes,” study leader David Nauen of Johns Hopkins University told Reuters. “They are so large that they can shut off blood flow through capillaries and restrict oxygen supply to the brain, which could affect brain function.” As reported Friday in the journal JAMA Neurology, his team studied brain tissue from 15 patients who died of COVID-19 and found megakaryocytes in five of their brains. “What signaled these cells to leave the bone marrow and travel to the brain is unknown, but COVID-19 causes disruptions in the coagulation system, and this may be related,” Nauen said.
Open https://tmsnrt.rs/3c7R3Bl in an external browser for a Reuters graphic about vaccines in development.
(Reporting by Nancy Lapid; edited by Will Dunham)