(Reuters) – Here’s what you need to know about the coronavirus right now:

Fauci warns against vaccine roll-out before safety checks

Distributing a COVID-19 vaccine under special emergency use guidelines before it has been proved safe and effective in large trials is a bad idea that could have a chilling effect on the testing of other vaccines, Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, told Reuters in a phone interview.

“One of the potential dangers if you prematurely let a vaccine out is that it would make it difficult, if not impossible, for the other vaccines to enrol people in their trial,” Fauci said.

Fauci said the U.S. Food and Drug Administration guidance on vaccines – both for full approval and for an EUA (emergency use authorization) – explicitly requires a demonstration that it is both safe and effective.

Hong Kong man reinfected with different strain

A 33-year-old Hong Kong man who recovered from, and was cleared of, COVID-19 in April tested positive again after returning from Spain via Britain on Aug. 15 in the first documented instance of human re-infection, researchers at the University of Hong Kong said on Monday.

The man was found to have contracted a different coronavirus strain from the one he had previously contracted and remained asymptomatic for the second infection.

The findings indicate the disease, which has killed more than 800,000 people worldwide, may continue to spread amongst the global population despite herd immunity, the researchers said. Jeffrey Barrett, an expert and consultant with the COVID-19 Genome Project at Britain’s Wellcome Sanger Institute, said in emailed comments to Reuters that it was very hard to make any strong inference from a single observation.

Seoul closes most schools, urges doctors back to work

South Korea on Tuesday ordered most schools in Seoul and surrounding areas to close and moved classes back online until Sept. 11, the latest in a series of precautionary measures aimed at heading off a resurgence in coronavirus cases.

Health Minister Park Neung-hoo on Tuesday pleaded with thousands of doctors who have been staging walkouts to return to work. The doctors are protesting several government proposals, including a plan to increase the number of medical students by 4,000 over the next 10 years.

The government says the plan is necessary to be better prepared for public health crises like the coronavirus pandemic, but doctors’ associations have said it would unnecessarily flood the market and do little to fix systemic problems.

“Genetic barcodes” could help monitor mutations

“Genetic barcodes” can help track how the new coronavirus spreads and mutates, researchers said on Saturday in the International Journal of Infectious Diseases.

Based on the organization, or sequence, of the genetic code of the virus, the researchers identified 11 distinct SARS-CoV-2 “barcodes” that represent different clades, or lineages, descended from a common viral ancestor.

Different continents have different variations, Arnab Pain of King Abdullah University of Science and Technology in Saudi Arabia and his team found. The subtle differences in the genetic sequences represented by the barcodes may affect virus infectivity or illness severity, Pain noted.

The researchers plan to regularly update the barcodes. “This is a dynamic process, and some virus clades/subclades may eventually die off in the future, and new clades may form,” Pain said.

(Compiled by Karishma Singh; editing by Jane Wardell)

Copyright 2020 Thomson Reuters.