Let’s talk about COVID-19 again. I want to share just a few paragraphs to simplify recent, good data that might lessen your anxiety over rising cases, the paradoxically increasing opportunities to spread this largely untreatable virus, and looming school start dates. And if you read no further the upshot is this: wear a mask and avoid places and situations where large numbers of people are enclosed in spaces without them.

For those of us in and around Boston, the numbers are promising. The effective reproduction rate of COVID-19 is now under 1; and when the R_T is under 1, the virus stops spreading. From a microbiological perspective, this makes no sense. COVID-19 has not mutated dramatically and we are nowhere near herd immunity making hosts for coronavirus harder to find. It’s simply our behavior that has led to this decrease. Every canceled concert, empty seat at Fenway, closed bar, masked wait staff at outdoor restaurants, and postponed graduation party helped. YOU helped. Good job, Massachusetts!

With the R_T below 1, our essential workers at grocery stores, pet groomers, and fast food joints are also safer. But as we relax stay-at-home orders, we need to personalize our own risk assessment: if you contracted COVID-19, how likely is it to kill you? When I first wrote about the novel coronavirus, citing data from Wuhan, 15% of patients required hospital care and the infection fatality risk (IFR) was over 5%. This number was terrifying as the scale of the disease was taking shape. Conservative estimates of 40% of the population ultimately contracting this virus could have resulted in 7 million Americans dying. This is why Dr. Fauci was on TV every night. Three months later, scientists have more data and that number has dropped dramatically. A promising study group from the Diamond Princess cruise ship tested all 3711 passengers and staff, effectively capturing even the asymptomatic carriers, and estimated an IFR closer to 1. As testing improved and widened, other studies (albeit quickly calculated and not-yet-peer-reviewed) found IFRs hovering between 0.5 and 1. And even if we’re still underestimating this, it’s a far cry from 5.

You can see here and here how well Massachusetts is doing IFR-wise. Another heartening statistic is a death rate of zero (ZERO!) for patients under 19. Unfortunately, these statistics don’t suggest we can stop worrying about Grandma. A closely studied population in Geneva stratified the IFR by age and found that in a city with sufficient hospital capacity and excellent medical care, the risk for those over 65 years of age is still between 4 and 7%. Other articles you have probably already read suggest that many of those patients are also overweight, diabetic, hypertensive, immune-compromised, etc. The best way to protect our elderly and at-risk loved ones is to prevent them from getting COVID-19 at all.

How?

Odds are, you’re already doing this. Masks masks masks, limiting exposure, and close surveillance of your own health. Back in March when tests were sparse and we had only just stopped doing spin class, Sunday mass, choir rehearsals, and travel team sports, we had no idea who in our midst could be carrying and spreading COVID-19. Strict shut down was essential. Today, scientists are less worried about you contracting coronavirus from your play dates and take-out containers than from a “superspreader.” Pockets of new cases arise as people with no symptoms (or let’s face it, probably a little under the weather but ignoring it) and who aren’t wearing masks unwittingly attend activities that should still be verboten. An alarming example out of India is cautionary: after a wedding reception where over 350 guests were somehow allowed, nearly 100 townsfolk were infected. Though most of those who contracted the disease were asymptomatic and ultimately isolated, the 30-year-old groom who had exhibited all of the telltale COVID-19 symptoms died only two days after the ceremony. This devastating case illustrates the tragedy that ensues when a person with a high viral titer (the groom) is widely exposed (parties over 20 people) in an enclosed venue (reception hall) at exactly the wrong time (active infection with droplet-spewing symptoms).

The Indian wedding example is what is happening in areas that now need to reverse course and reinstate restrictions. As unmasked young people flocked to restaurants, bars, and parties, it took only one superspreader in their midst to undo three months of curve-flattening. Those who continue to hawk conspiracy theories and politicize mask usage will use new data to their advantage. Whoo-hooing revelers who contract the virus and don’t die (because they are young), will cause the IFRs to drop even lower. COVID-19 remains as deadly as it was in Wuhan in December, but will seem like it’s petering out.

It’s not.

So wasn’t this supposed to be an essay to alleviate your worries and bolster your confidence to send bored kids to camp and (please please please) back to school? Yes. Yes it is. The kids are alright, as the saying goes. And yesterday, Massachusetts posted its first day of zero (ZERO!) COVID-19 related fatalities. Unfortunately our at-risk population will need to remain vigilant until we have herd immunity (not happening any time soon) or a vaccine. I am loathe to give you my hunch about a vaccine, so let’s leave it at this: keep wearing masks and washing your hands, postpone parties, see friends outdoors… and maybe we’ll R_T this thing to oblivion.

If Captain Kirk can wear a mask (while supporting the local bookstore… swoon…), let’s boldly join him in doing so.