The Latest: New clues in a Covid-19 mystery

Alexandra Sifferlin
Medium Coronavirus Blog
3 min readSep 25, 2020


Dear Reader,

One of the greatest mysteries of the Covid-19 pandemic is why some people who get the virus have very severe infections and other people have mild cases — or don’t appear to produce any noticeable symptoms at all.

READ: Scientists Identify Genetic Factors That May Explain Severe Covid-19 Cases

Scientists have long believed there might be a genetic component to this phenomena and launched the Covid Human Genetic Effort to look at biological factors that might be at play. Yesterday this team published its first two studies. You can read about the findings here and further down.

Follow our Medium Coronavirus Blog for regular updates, and read some of the essential stories we’ve curated below.

Be well,

Alexandra Sifferlin
Editor, Medium Coronavirus Blog

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Here’s what we’re talking about on the blog:

The latest vaccine news. This week, Johnson & Johnson and Novavax’s Covid-19 vaccine candidates advanced to the final stages of clinical trials, which brings the number of vaccines in phase 3 trials to 11. Johnson & Johnson’s vaccine may have an advantage over its competitors because it could need only one shot instead of two and doesn’t have to be kept frozen. Read more news from the vaccine race here.

What underlies a severe Covid-19 infection? In two new studies published in the journal Science, research identifies potential immune system weaknesses that may affect how a person’s Covid-19 infection plays out. A notable portion of people who develop severe symptoms have “misguided” antibodies that attack a person’s immune system instead of the virus. Among the people studied, this abnormal immune response occurred much more often in men (which might offer some explanation as to why more men die from Covid-19 than women). There are other important findings too, and you can read about them here.

Five criteria for easing lockdowns. In a new study, researchers compared the strategies for easing lockdown restrictions in nine countries and regions in Europe and the Asia Pacific, and they identified five key indicators for a country’s success, including: knowledge of infection levels, community engagement, public health capacity, health system capacity, and border control measures. Some countries were better at these measures than others. For example, contact tracing was much more successful in countries like South Korea and Singapore. Wearing face masks was more common in Asia than in Europe. And experiences with previous outbreaks like SARS meant several Asian countries also had more robust health care systems in place. Read more.

People hated seat belts, too. The history of seat belt sentiment in the U.S. (people did not like them or want to wear them for years!) is an important reminder that Americans have a long tradition of pushing back initially — and strongly — to requests and requirements that they change their behavior, even if there’s a clear benefit to themselves and others. This was the case with seat belts, and could be the case with face masks, too. Read how the backlash subsides.

Enough with the vaccine hesitancy hand-wringing. You heard that right. There’s been a lot of media attention given to polls that suggest many Americans are uncertain about getting a Covid-19 vaccine. But as vaccine reporter Tara Haelle writes, there are much bigger issues to worry about than some early doubts. Having questions or concerns about a brand-new vaccine is normal, and with education and evidence, there’s a good chance people with early misgivings will come around. Read more here.

A few more smart reads

The U.S. Assault on Seniors Is Deadly

The End of the Booming Mask Economy Is Near

In the Race for a Covid-19 Vaccine, Slow Starters Could Still Win Out (STAT)

The Nose Needed for This Coronavirus Test Isn’t Yours. It’s a Dog’s.(New York Times)



Alexandra Sifferlin
Medium Coronavirus Blog

Health and science journalist. Former editor of Medium’s Covid-19 Blog and deputy editor at Elemental. TIME Magazine writer before that