Severe

Empty vials containing a dose of the Johnson & Johnson vaccine against the COVID-19 coronavirus lie on a table as South Africa resumes its vaccination campaign at Klerksdorp Hospital on February 18, 2021.Phill Magakoe | AFP | Getty…

"We're getting more of these MIS-C kids now, but this time it just seems like a higher percentage of them are really seriously ill," said Dr. Roberta DeBiasi, Infectious Disease Director at Children's National Hospital in Washington. DC…

A pharmacist shows a box of tocilizumab, which is used to treat rheumatoid arthritis, in the pharmacy of Cambrai Hospital in France on April 28, 2020.Pascal Rossignol | ReutersA drug used to treat people with rheumatoid arthritis appears…

At first glance, the results reported on Friday of the long-awaited study of Johnson & Johnson's coronavirus vaccine may have been disappointing. Overall effectiveness - the ability to prevent moderate and severe illnesses - was…

It will be difficult "to find and diagnose them in this vanishingly small window," said Dr. Ilan Schwartz, an infectious disease doctor at the University of Alberta who was not involved in the study. "The study looks solid, but it isn't…

A pharmacist dilutes the Pfizer COVID-19 vaccine as he prepares it for administration to staff and residents at Goodwin House Bailey's Crossroads, a senior community in Falls Church, Virginia, on December 30, 2020.Brendan Smialowski | AFP…

Brain scans, spinal fluid analyzes, and other tests did not reveal any brain infection, said Dr. Gabbay, whose hospital has treated two patients with postcovid psychosis: a 49-year-old man who heard voices believing he was the devil and a…

Moderna's vaccine, like Pfizer's, is based on a molecule called messenger RNA, or mRNA, that is injected into the upper arm. Once inside human cells, the mRNA directs the production of a protein called spike, which teaches the immune…

However, in the early days of the Moderna study, there were fewer cases of Covid-19 among study participants, making it more difficult to measure the differences between the vaccinated group and the placebo group. In either case, health…