I shouldn’t be writing this.  I have no training in medicine or epidemiology.  I’m just some random person.  And if you have something from a better trained source that tells you how to manage your exposure to airborne infectious diseases like COVID, the flu or RSV in order to avoid passing it on to others and perpetuating the pandemic, you should probably go with that.

Unfortunately, our expert doctors and epidemiologists at organizations like the United States Centers for Disease Control and Prevention, and the World Health Organization, haven’t provided any guide for people who want to avoid passing COVID or other airborne diseases on to others.  Their guides focus on telling people how to minimize the risks to themselves.  They assume that everyone is a selfish asshole.

I’ll talk about what I’ve tried, but again, I’m just one person, with three close people in my family.  I have no way of doing an exhaustive study of the transmission of COVID or the flu.  My priorities are different from those of many other people.  So are the strengths and weaknesses of my body, my family’s bodies, and our risk tolerance.  So what works for me – or doesn’t – may well work differently for you.

We’ve also only had four years of COVID.  Our understanding of it is constantly evolving, and the disease itself is constantly evolving, so that what works one year may not work in the next.

With that in mind: a year ago I articulated a provisional strategy for balancing my wants and needs, and those of my family, with our desire to avoid catching COVID (and other infectious diseases), spreading it to others, and perpetuating the disease.

I plan on doing the following for the rest of my life:

• Wearing an N95-type mask in medical settings, including pharmacies
• Monitoring outbreak warnings
• Monitoring hospitalization rates for COVID, the flu and RSV
• Getting tested regularly during outbreaks

During an outbreak, I plan on:

• Wearing an N95-type mask in indoor public spaces
• Eating outdoors
• Organizing events online/outdoors
• Avoiding risky activities like singing

When I’m sick, I plan on:

• Staying home as much as possible
• Isolating from my family

This much is fairly straightforward, but the key questions are when to switch between regular mode, outbreak mode and sick mode, and back.  First of all: which indicators should we watch, and what will tell us that it’s a good time to change our behavior?

Hospitalizations and deaths per population are the indicators that seem to fit most closely with what we care about with COVID.  The mild cases I’ve experienced are no fun, but they’re not much worse than what I’ve had for colds, flu, strep or other respiratory infections.  Death is the worst outcome, but we want to prevent people from getting infections that are so bad they are admitted to the hospital.  We really need a good measure of Long COVID, but as of writing we don’t have one.

Hospitalizations and deaths are trailing indicators – they tell us what happens after infections – so they are good for conservative estimates about when to relax our precautions.  They can be compared across time and geographic area by counting the number of deaths or hospitalizations for a fixed number of residents of that geographic area.  Dividing by 100,000 gives us nice easy numbers that are usually between 1 and 100.  100,000 is a standard quantity in Indian arithmetic: one lakh.

Last year I found out from the Centers for Disease Control and Prevention that the nationwide peak of hospitalizations during flu seasons before COVID was around 6 per lakh, flu and RSV combined.  That means that before COVID we were tolerating six people in the hospital with flu and RSV every day, and not taking extraordinary measures like lockdowns or working from home.  I decided that that was a good benchmark: when the combined hospitalizations for flu, RSV and COVID are below 6 per lakh, it’s no worse than what we used to tolerate in 2019.

We can tell when we’re below 6 hospitalizations per lakh nationwide, but how easy is it to check that locally?  I’m fortunate that the New York City Department of Health and Mental Hygiene publishes regular reports of citywide COVID cases, hospitalizations and deaths.  The data is compiled by day; in 2021 and 2022 these reports were updated daily, but as of writing in May 2024 they are updated weekly.

Data for influenza and respiratory syncytial virus is much less comprehensive.  Both the CDC and New York City release weekly reports during the infectious seasons for these diseases, but while the CDC measures hospitalizations, New York City does not. That means there is a nationwide way of measuring the cumulative risk of catching or spreading any of the three diseases, but locally we can only measure COVID and guess at flu and RSV.

Eyeballing the data from the most recent winter wave, it looks like COVID cases constituted roughly half of hospitalizations nationwide.  It’s quite possible for flu and RSV hospitalizations to outpace COVID or vice versa, but as a first approximation we can say that if COVID cases drop below three hospitalizations per lakh residents per day, we are no longer in an outbreak and can relax some precautions, like eating and singing indoors.

That is the principle I used to determine when to start organizing in-person meetups for the New York Tech Karaoke Meetup, where I am an organizer, and in general to switch from outbreak mode to normal mode. Switching from normal mode to outbreak mode is a different challenge that deserves a separate blog post. Spoiler alert: I failed to take adequate precautions in December 2023 and was sick with COVID, so I’ll talk about some lessons learned from that experience.