COVID-19: Human Challenge Trial / Masks on Public Transportation / Mortality in NYC

By Amy Orciari Herman

Edited by David G. Fairchild, MD, MPH, and Lorenzo Di Francesco, MD, FACP, FHM

Here are some of the latest developments in COVID-19:

Human challenge trial: U.K scientists on Tuesday announced plans for a human challenge trial to determine the minimal amount of SARS-CoV-2 that's needed to cause an upper respiratory tract infection. Beginning in January, healthy young adults quarantined at the Royal Free Hospital in London "will have a purified, laboratory-grown strain of the live virus blown into their noses," the Washington Post reports. They will then be tested "daily, even hourly ... over two to three weeks." A later phase of the trial will involve vaccinating new volunteers and then exposing them to SARS-CoV-2 to assess the vaccines' efficacy.

Masks on public transportation: The CDC on Monday made a strong recommendation that passengers on public transportation — and transportation workers — wear face masks to help prevent SARS-CoV-2 transmission. This includes airplanes, buses, ferries, ride-shares, ships, subways, taxis, and trains. The guidance specifies that "people should wear masks that cover both the mouth and nose when waiting [for], traveling on, or departing from" public transportation (for example, masks should be worn both in the bus terminal and on the bus). Additionally, operators should not allow people to board unless they have a mask on. The guidance lists exceptions — for instance, children under age 2 years should not wear a mask, and a physician's note may advise that an individual not wear one for medical reasons.

Mortality in New York City: The overall estimated COVID-19 infection-fatality risk in New York City between early March and June was 1.4%, according to a study in The Lancet Infectious Diseases. For adults aged 65 through 74, the fatality risk reached 4.9% and for those aged 75 and older, 14.2%. Among younger groups, the infection-fatality risk was far lower — 0.01% for those under 25 years, 0.12% for those aged 25 through 44, and 0.94% for those aged 45 through 64. The findings were based on an analysis of more than 205,000 COVID-19 cases and 21,000 confirmed and probable deaths.