It’s Not Whether You Were Exposed to the Coronavirus. It’s How Much.

When experts recommend wearing masks, staying at least six feet away from others, washing your hands frequently and avoiding crowded spaces, what they’re really saying is: Try to minimize the amount of virus you encounter.

A few viral particles cannot make you sick — the immune system would vanquish the intruders before they could. But how much virus is needed for an infection to take root? What is the minimum effective dose?

A precise answer is impossible, because it’s difficult to capture the moment of infection. Scientists are studying ferrets, hamsters and mice for clues but, of course, it wouldn’t be ethical for scientists to expose people to different doses of the coronavirus, as they do with milder cold viruses.

“The truth is, we really just don’t know,” said Angela Rasmussen, a virologist at Columbia University in New York. “I don’t think we can make anything better than an educated

Read More

Blaming China for Pandemic, Trump Says U.S. Will Leave the W.H.O.

After spending weeks accusing the World Health Organization of helping the Chinese government cover up the early days of the coronavirus epidemic in China, President Trump said on Friday that the United States would terminate its relationship with the agency.

“The world is now suffering as a result of the malfeasance of the Chinese government,” Mr. Trump said in a speech in the Rose Garden. “Countless lives have been taken, and profound economic hardship has been inflicted all around the globe.”

In his 10-minute address, Mr. Trump took no responsibility for the deaths of 100,000 Americans from the virus, instead saying China had “instigated a global pandemic.”

There is no evidence that the W.H.O. or the government in Beijing hid the extent of the epidemic in China, and public health experts generally view Mr. Trump’s charges as a way to deflect attention from his administration’s own bungled attempts to respond

Read More

C.D.C. Suggests Big Changes to Offices: Temperature Checks and Desk Shields

Upon arriving at work, employees should get a temperature and symptom check.

Inside the office, desks should be six feet apart. If that isn’t possible, employers should consider erecting plastic shields around desks.

If followed, the guidelines would lead to a far-reaching remaking of the corporate work experience. They even upend years of advice on commuting, urging people to drive to work by themselves, instead of taking mass transportation or car-pooling, to avoid potential exposure to the virus.

The recommendations run from technical advice on ventilation systems (more open windows are most desirable) to suggested abolition of communal perks like latte makers and snack bins.

“Replace high-touch communal items, such as coffee pots, water coolers, and bulk snacks, with alternatives such as prepackaged, single-serving items,” the guidelines say.

And some border on the impractical, if not near impossible: “Limit use and occupancy of elevators to maintain social distancing of at

Read More

Scientists Question Major Hydroxychloroquine Study

More than 100 scientists and clinicians have questioned the authenticity of a massive hospital database that was the basis for an influential study published last week that concluded that treating people who have Covid-19 with chloroquine and hydroxychloroquine did not help and might have increased the risk of abnormal heart rhythms and death.

In an open letter to The Lancet’s editor, Richard Horton, and the paper’s authors, the scientists asked the journal to provide details about the provenance of the data and called for the study to be independently validated by the World Health Organization or another institution.

A spokeswoman for Dr. Mandeep R. Mehra, the Harvard professor who was the paper’s lead author, said on Friday that the study’s authors had asked for an independent academic review and audit of their work.

Use of the malaria drugs chloroquine and hydroxychloroquine to prevent and treat Covid-19 has been a focus

Read More