Tear gas flavor ice cream

Our projections suggest warmer and more humid times of the year, and locations, may offer a modest reduction in reproductive number;  however, upcoming changes in weather alone will NOT be enough to fully contain the transmission of COVID-19. 

112 persons were infected with SARS-CoV-2 associated with fitness dance classes at 12 sports facilities. Vigorous exercise in confined spaces should be minimized during outbreaks. […] Instructor C taught Pilates and yoga for classes of 7–8 students in the same facility at the same time as instructor B, but none of her students tested positive for the virus) [CDC]

Even before Vietnam reported its first cases on 23 January, it was on high alert for Covid-19.

At one Lima market, 79% of vendors had coronavirus

There is a common misunderstanding that the social benefits of a share of the population acquiring immunity to a disease kick in only once a critical mass is reached (60% or 70% have often been quoted in the context of this new coronavirus). In fact, the social benefits start accruing from the very start of an epidemic and can be significant even when a relatively small share of the population has acquired immunity. As a result, subsequent waves of the epidemic may be somewhat easier to manage, with a slower build-up of cases for any given level of social distancing and effectiveness of test, trace and isolate (TTI) processes. Equivalently, it may be possible to suppress subsequent waves with less social distancing than was the case during the initial wave – with this effect being even stronger if the effectiveness of TTI also improves. [Alma Economics]

Herd Immunity sounds promising for a once-in-a-lifetime disease. But if immunity only lasts 12 to 24 months, that’s a several times per decade disease, which sounds like a less attractive deal. Let’s say the Infection Fatality Rate is just 0.5% per run to Herd Immunity, which would be achieved at, say, 60% of the US population of 330 million or about 1,000,000 deaths each time. […] Advocates of a Herd Immunity strategy really need to get out their spreadsheets and do the math of how this would turn out to be a good thing. Perhaps it is the best alternative, but, please, show your work. [Steve Sailer]

The two drivers of the spread of the disease are close contact and crowding in closed spaces

Getting a handle on asymptomatic SARS-CoV-2 infection

It’s safer to be outside than in the office or the mall. With fresh air and more space between people, the risk goes down. But experts also expressed particular caution about outdoor dining, using locker rooms at pools and crowds in places like beaches. […] Practice social distancing and wear a mask when that is not possible. Ideally, people should socialize only with people who live in their homes, they say. If you decide to meet friends, you’re increasing your risk, but you can take precautions. It’s important to keep gatherings small. Don’t share food, utensils or beverages; keep your hands clean; and keep at least six feet from people who don’t live in your home. […] While the risk of outdoor transmission is low, it can happen. In one study of more than 7,300 cases in China, just one was connected to outdoor transmission. In that case, a 27-year-old man had a conversation outdoors with a traveler who had just returned from Wuhan. Seven days later, he had his first symptoms of Covid-19. [NY Times]

Loud talking could leave coronavirus in the air for up to 14 minutes (The study was also run in a tightly controlled environment, and it did not account for the types of air circulation and temperature changes you would find in nearly any real-world environment.)

Across Sweden, almost 30 percent more people died during the epidemic than is normal during this time of year, an increase similar to that of the United States and far higher than the small increases seen in its neighboring countries. […] Swedish officials chose not to implement a nationwide lockdown, trusting that people would do their part to stay safe. Schools, restaurants, gyms and bars remained open, with social distancing rules enforced, while gatherings were restricted to 50 people. Two months later, it has not been the worst-case scenario many envisioned. […] But there is reason to believe that Sweden’s approach may not work as well elsewhere. But there is reason to believe that Sweden’s approach may not work as well elsewhere. […] And although Sweden is not a particularly young country in comparison with its Western European peers, it has a high life expectancy and low levels of chronic diseases, like diabetes and obesity, that make the virus more lethal. [NY Times]

Tear gas is among the new flavors at a Hong Kong ice cream shop.