In case it helps even one of my readers in a practical way, I wanted to collect some of the most useful news snippets I have seen recently about Covid-19 science. Most of this is a confirmation of what I said in “4 Types of Heterogeneity that Offer a Bit of Extra Hope for Keeping the Pandemic Under Control without Blanket Lockdowns”: (a) number of people and (b) duration of contact matter as much as (c) distance and (d) masks. For example, take this passage from Jennifer Calfas’s June 18, 2020 Wall Street Journal article, “California Requires Face Coverings as Some States See Daily Record Cases”, which adds (e) ventilation and (f) talking loudly:

Recent findings among researchers and scientists show close-up interactions, crowded events, poorly ventilated areas and places where people are talking loudly maximize the risk of contracting the virus. Fleeting encounters with people outdoors and contaminated surfaces are less of a risk. These findings are helping shape policy as the Centers for Disease Control and Prevention urges Americans to keep wearing masks and maintaining distance as reopenings continue.

Other sources emphasize that singing has the same kind of malign effect as talking loudly. Peggy Noonan’s June 11, 2020 Wall Street Journal op-ed, “Get Ready for the Second Coronavirus Wave” adds that in addition to good ventilation outside, the sunlight and the now more and more common warm temperature outside can reduce transmission:

Coronavirus doesn’t like sunlight, fresh air or warm temperatures. It prefers coolness and poor ventilation in enclosed places, meatpacking plants being the most famous example.

For me the bottom line is: if you can help it, don’t be inside with someone else you don’t live with—and especially not with a lot of someone else’s—for any extended period of time. If you are, masks don’t mean there is no danger, but they help. And even outdoors, if you are going to be in a large gathering despite the danger, make sure to wear a mask and urge others there to wear one. Don’t be like Debbie Tutor, interviewed for Alejandro Lazo, Andrew Restuccia and Joshua Jamerson’s June 19, 2020 Wall Street Journal article “On Juneteenth, Tulsa Prepares for Unrest as Protesters March Nationwide”

Debbie Tutor, 60, of Wichita, Kan., was among those waiting in line. A longtime Trump supporter, she said it was her first time attending a rally. “I’m just here to support him,” she said.

Ms. Tutor, like the others waiting outside the arena, wasn’t wearing a mask and said she isn’t worried about the coronavirus spreading among rally attendees. She asserted that the president’s opponents are amplifying the health threat to hurt his re-election.

On ideas about how to reduce the danger of a bad outcome from the novel coronavirus conditional on becoming infected, see my posts:

• Eating During the Coronavirus Lockdown

• Interactions between COVID-19 and Chronic Diseases

• Getting More Vitamin D May Help You Fight Off the New Coronavirus

• Can Fasting Help Fight the Coronavirus?

• Sugar Puts You in Greater Danger from Covid-19

If you haven’t had Covid-19 yet, regardless of your other current health conditions, I believe it will materially help your chances if you do get infected later on to go off sugar right now and making sure you get plenty of Vitamin D—more than the miscalculated minimum daily requirement: see “Carola Binder—Why You Should Get More Vitamin D: The Recommended Daily Allowance for Vitamin D Was Underestimated Due to Statistical Illiteracy.”

The importance of going off sugar immediately (and ideally reducing your eating window each day to as few hours as possible) in order to reverse chronic diseases that put you in greater danger from Covid-19 is emphasized by the statistics on who is dying from Covid-19. We all know that older people die with a greater probability if they get the disease, but a substantial fraction of that age difference may be due to the fact that older people tend to have a greater burden of chronic diseases. Two articles give interesting statistics relevant for this.

First, from the June 12, 2020 Wall Street Journal Editorial “The Covid Age Penalty”:

Older people generally have weaker immune systems and more have underlying respiratory and cardiovascular conditions that appear to exacerbate the illness. More than 95% of people who have died in the United Kingdom had at least one underlying condition. Italian public-health officials have also reported that 96% of deaths involved one chronic condition, and 60% had three or more.

Nursing homes are especially vulnerable because they have large numbers of elderly in cramped quarters. They now account for more than 50% of Covid-19 fatalities in 30 or so states, including Arizona, Washington, Illinois, Pennsylvania and Massachusetts.

The good news is that most people over age 65 who are in generally good health are unlikely to die or get severely ill from Covid-19. Data from Spain’s national antibody study show that about 92% of those infected from ages 60 to 79 have mild or no symptoms, and only about 6% are hospitalized. Three-quarters of people older than 90 have mild or no symptoms and fewer than 10% die.

Second, from David Luhnow and José de Córdoba’s June 19, 2020 Wall Street Journal article, “As Covid-19 Hits Developing Countries, Its Victims Are Younger”:

Another reason fewer older people are dying in poorer nations is the lack of institutionalized care for the elderly. An estimated one-third or more of deaths in the U.S. have taken place in nursing homes, where the virus can easily spread among those most vulnerable. In countries like Mexico, the elderly usually live with their families, making it less likely they pass it on to other at-risk elderly, said Mr. González-Pier.

But health is a bigger factor. Dr. Alejandro Macias, a specialist in infectious diseases who played a leading role in halting the H1N1 pandemic in 2009, says the main reason the country’s Covid-19 victims are much younger than in the U.S. has to do with the prevalence of a host of unhealthy conditions—obesity, hypertension, and diabetes chief among them.

More than 4 in 10 people who have died in Mexico from Covid-19 had hypertension, roughly 4 in 10 had diabetes, and a quarter were overweight, according to government statistics.

Conclusion: I hope this is helpful. One more resource I have found useful is the May 27, 2020 Wall Street Journal podcast, “Is Banning Certain Events the Key to Reopening?”

New insights in Covid-19 continue to emerge. I hope we soon understand it much better than we do now.