Death rates. Case rates. Case rates in proportion to testing. Recoveries. Hospitalizations.
The numbers of the COVID-19 epidemic are stark. At the time of writing the US has recorded over 1.2 million confirmed cases, with the true number likely higher, and a bit over 72,000 deaths.
People under lockdown are watching for case counts per day to start falling.
We’re all paying so much attention to numbers, but there’s one which isn’t getting enough attention.
That number is the R0.
What is R0?
R0 (R naught) is a mathematical term that’s used to gauge the contagiousness of an infection.
A disease’s R0 is the average number of people any given patient infects. It’s short for basic reproduction number, and assumes that all individuals in the population are susceptible to infection.
R0 is calculated by epidemiologists, and it’s not generally measured directly, but rather through models. Discussing it, therefore, comes with some caveats.
However, it’s still a vital number.
What is COVID-19’s R0, and How Does it Compare to Other Diseases?
The R0 of COVID in an unprotected population is somewhere between 2.5 and 3 (R0s are generally given as a range, to reflect variation. This means that each patient will infect, typically, 2 or 3 other people. That’s the exponiential growth people are talking about. Even at the best case scenario your cases go from 1 to 2 to 4 to 8 to 16 and so forth.
This compares with a number of other diseases as follows:
- Influenza — 1.3
- Measles — 18 (this is only one of a number of reasons why measles is so scary. Vaccinate your kids).
- SARS — 4
- HIV — 4
- Hepatitis C — 2
- Smallpox — 5–7 (aren’t you glad it’s gone).
R0 doesn’t necessarily mean pandemic. Ebola has a R0 of 2, but doesn’t spread that quickly because it’s so lethal. But a higher R0 indicates higher potential threat. Also, bear in mind that it is an average. Super spreaders such as Patient 31 in South Korea pull the R0 of the disease upwards in a way that might not reflect real risk.
Can we Change the R0?
The really important thing about R0 is that we can change a disease’s effective R0.
By this we mean the actual R0 on the ground in a specific community.
An R0 of above one means a disease is spreading. The reason influenza is seasonal is because its effective R0 goes above 1 in the winter due to colder and dryer air and people spending more time indoors. You can still get the flu in the summer, it’s just a lot less likely.
An R0 of less than one means a disease is dying out.
And the good news is: You can actually reduce the effective R0. Yes, you right there reading this article can reduce the R0 of COVID-19, and if enough of us do, we can defeat the virus without having to wait for a vaccine or a cure.
How do we Reduce the R0?
You aren’t going to like it.
We reduce the R0 by:
- Staying home when it isn’t necessary to go outside.
- Wearing masks in public.
- Washing our hands.
- Staying home and isolating ourselves as much as possible when sick.
Yeah, all those things you’re being told to do are about reducing the effective R0.
Now, of course, we’ve all gotten impatient and want to get on with our lives. So let’s look at these measures:
Okay, none of us like being in quarantine. I hate it. But even after your state lifts mandatory stay at home measures, you should continue to consider whether you need to go out. Why are you going outside? Really, you should be going out only:
- To buy things you need. Under stay-at-home that’s limited to food and medicine, but after things ease off and stores reopen, you can consider carefully going out to get clothes, supplies for your crafting, etc.
- To benefit your mental or physical health. Please exercise. If an activity is what you do instead of therapy, do it. Your immune system needs it.
- To help somebody else who can’t go outside. Particularly vulnerable people should be staying home for a good while yet. Getting groceries for grandma is fine.
- To care for animals.
- To work if you have to work outside the home. If your job can be done remotely and your boss will let you, keep working from home.
It’s harsh, but it’s reality. The more we go out, the higher the effective R0, and we have to keep it below that magic one. That also means that you shouldn’t be expecting to go to a concert, sporting event, conference, or crowded bar any time soon. Don’t worry, those things will all come back, even if we have to rebuild them from scratch. But I’m not expecting to go to a convention until 2021 unless things go much better than I expect.
Wearing a Mask
We all hate them. Hate them. But even a basic cloth mask helps. You should wear a mask any time you go outside, including to exercise. I’m not looking forward to it when the weather stops being so ridiculously unseasonably cold here.
Now, the reason you wear a mask is not to protect you. Healthcare workers wear PPE that is designed to protect them. Handmade cloth masks won’t do that.
It’s to protect everyone else. With a 14-day incubation period, high number of asymptomatic carriers, and a highly contagious period right before symptoms show up, COVID is a nightmare to contain. We have to assume we are all sick. (Even if you think you’ve already had it. We don’t know how long immunity lasts, and although it’s likely it will last a year or two, we shouldn’t be assuming).
And, of course, if everyone is wearing masks, we’re all protected. Now, some people can’t wear masks. Children under 2 should not wear masks. I know of some people who have experienced migraine after wearing a mask, some people who have difficulty breathing, and have heard of claustrophobia and panic attacks.
Like vaccinations, we just need to get compliance high, not perfect.
You also need to wear your mask correctly. Avoid touching or adjusting your mask as much as possible, especially the front of the mask. If you do, wash your hands. Your mask must cover both your nose and your mouth. No, you should not put your mask on only to enter a confined space…putting your mask on as you enter the grocery store and then touching everything in the store is not helpful. Your mask is not helpful if it is below your chin, covering only your mouth or, and I have seen this, dangling from one ear.
Oh, and it is really not helpful if you take it off to cough! (Which I’ve also seen).
You should only remove your mask in public to eat or drink, and if you do so you should put your mask in a bag of some kind, not on a surface somebody else has to clean. Wash your hands, if possible, before and after removing or donning your mask.
It’s not published, but Arizonan scientists feel that if 80% of us wear masks, we can reduce the death rate by 17–45%…and that’s in areas with very high transmission risk such as New York.
Please wear your mask.
Wash Your Hands
You’ve heard this one a thousand times already. But yes, you need to wash your hands for 20 seconds in soap and water. If soap and water aren’t available, use hand sanitizer with at least 60% alcohol.
Stay Home When Sick
Finally, stay home when you are sick. We need, as a society to stop with the pressure to work through it. Don’t come out until you are completely better, even if you think it’s a mild cold (Okay, allergy sufferers, I feel you).
If we do all of these things, we may well be able to keep the R0 below 1 and wipe this thing out.
And we can’t always count on the government to do them for us. Find ways to support businesses that aren’t going outside a lot.
And wear your mask. It might make all the difference.