Preparing not Panicking: Finding Good Information in a (Potential) Pandemic

Updates 13 March 2020: I’ve updated the data tables and analysis below, as well as noted the new WHO estimates for case-fatality rate as being 3-4%.

Since writing this, the United States and Europe have begun seeing high levels of community-level transmission. This means that people are being exposed to COVID-19 and becoming sick while out in their community without contact with a person known to have the disease. Because of this, broad scale social distancing measures are being implemented and all of us should be complying with them to the degree we absolutely can.
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I’ve said this on the about page, but I want to start this post with three disclaimers:

I am not authorised to speak on behalf of my employers regarding this situation. I am speaking as a private citizen with expertise in communicable disease epidemiology.
I am not a clinician and cannot give you (or anyone ever) medical advice.
This post should not replace the information that public health agencies are sharing. I’m simply collating some of it into a single place because I’ve gotten so many questions and sharing huge blocks of links is challenging. A list of public health websites I like to check is included at the bottom of this post.

Now, with that sorted, let’s talk about novel coronavirus, known as COVID-19.

Global cases of COVID-19 by country, from the World Health Organisation (12 March 2020 20:30 PST)

COVID-19 and Coronaviruses

COVID-19 is a respiratory illness caused by the novel coronavirus SARS-CoV-2. Coronaviruses are a family of viruses (like influenza viruses are a family of viruses) and circulate in our communities every year. They usually cause mild, flu-like illness and don’t require hospitalisation or complex medical care. Notable exceptions to this were SARS (Severe Acute Respiratory Syndrome) and MERS (Middle Eastern Respiratory Syndrome). This coronavirus is new (novel) to humans and so public health scientists are still learning a lot about it. Like other coronaviruses, this one seems to be a zoonotic infection and crossed into humans from an animal—likely bats.

COVID-19 transmission

A comparison of the basic reproduction number (R0) of several viral infections via PopSci

Like other coronaviruses, the primary methods for transmission from person-to-person are through respiratory droplets (when someone coughs, sneezes, or spits) and contact with infected surfaces. Some easy tips to help reduce your risk of infection are included in another section below.

How easily COVID-19 spreads between people is still being discussed, but current modelling (using cool math and fast computers) suggests that it spreads more easily than seasonal influenza and less easily than SARS did. Epidemiologists use a number called the Basic Reproduction Number (R0, pronounced “R naught”) to estimate the number of new infections on average we expect each person to generate. For a disease like measles, it’s about 16 (range is 12-18); for pertussis (the whooping cough), it’s about 5.5. For COVID-19, it seems to be about 2.8 (1.5-3.5).

COVID-19 symptoms

COVID-19, like its coronavirus brethren, causes fever, cough, and breathing difficulty. Public health scientists estimate 80% of people who come down with COVID-19 would experience mild symptoms and not need hospitalisation. Several cases in Washington State alone have managed their own illness without hospitalisation.

While most people will have very mild illness, some people may get quite ill. Epidemiologists use a simple calculation called a Case-Fatality Rate to measure this. We divide the number of people who die from a disease (Fatalities) by the number of people who had the disease (Cases). This number is about 0.1% for seasonal influenza in the United States and 3.4% overall for COVID-19. However, public health scientists expect that most of the severe illnesses will be in patients who are older. They also expect that most deaths will occur among older individuals. Avoiding death completely is the ideal, of course, but better understanding who is most likely to get the sickest and how to treat them helps hospitals make sure those people get the care they need.

If you have these symptoms, especially if you’ve had contact with someone with COVID-19 or have recently travelled somewhere effected (e.g., Italy, South Korea, Mainland China), you might consider contacting your healthcare provider. If you go to the hospital or a clinic, you should call ahead and let them know your health situation and that you’re coming.

Preventing COVID-19

Fortunately, preventing COVID-19 infections is a lot like preventing the flu.

Wash your hands often with soap and warm water for at least 20 seconds. A video showing the World Health Organisation (WHO) hand washing technique here.
- If you’re in the mood for something amazing, the Washington State Department of Health has a very catchy jingle—Washyourhandsington—which is a good length of time for scrubbing.
- If you can’t wash your hands, it’s fine to use a hand gel/sanitiser as a back up, but it should be at least 60% alcohol.
Cough and sneeze in your elbow. Maintain good respiratory hygiene, including washing your hands after blowing your nose.
Avoid touching your face. This one is so, so hard for me (I’m forever touching mine), but hands can be quite unclean and faces have a lot of mucous membranes which can be an entry point for germs.
Stay home if you’re sick. If it’s at all possible to stay home when you’re unwell, you should. Children shouldn’t go to school if they’re poorly and adults should not go to work.
Clean frequently touched surfaces. We’re still learning about COVID-19’s ability to live on surfaces, but public health scientists are fairly sure can spread through contact with infected surfaces the way other coronaviruses do.
If your area is experiencing community-level transmission, stay home when you can and maintain some distance (6 feet) from people as much as possible if you do need to go out. Social distancing is an important component of mitigating community-level transmission.
Prepare plans to work from home and for childcare if schools close. If your area is experiencing community-level transmission (spread) of COVID-19, your local health officials may recommend closing schools, cancelling or postponing large gatherings, or other measures.
Follow CDC directions about using masks. It’s important to remember that masks, in general, keep germs in not out. The CDC and FDA do not recommend wearing masks in the community for well people. Respirator masks (N95 masks) should be professionally fit tested to be effective. If you don’t need a mask, please remember that supply chains could be effected and healthcare workers need them.
Stay aware of travel advisories. The US State Department maintains a page here listed by country (there’s a search bar) which I find quite handy.
Remember to be kind. People of East Asian descent are not more likely to catch COVID-19 than other individuals. Chinese people are not to blame for COVID-19. Viruses don’t discriminate and neither should we.

COVID-19 cases in the United States

As you can see, several states have cases, but most of them involve travel (typical or repatriation-associated) and the cases themselves are concentrated in a relatively small number of states.

States with COVID-19 cases, from the Centers from Disease Control and Prevention (14 March 2020 06:30 PST)

Counts of US Cases, from the Centers for Disease Control and Prevention (12 March 2020 20:30 PST)

We are now seeing local transmission in many areas, but Public Health is taking steps to control the spread of COVID-19. Dr. Robert Redfield and Dr. Nancy Messonnier of the CDC both stated in early March that it was likely there will be at least some degree of community-level transmission in the US. They and other public health practitioners have encouraged people to remember this is a time to plan, not to panic. Things are very serious and we need to be careful, but swift and decisive action can help protect communities.

Case reporting in the United States is complicated, so the table below is taken from data on the CDC’s United States situation summary page. It shows case counts in a way that, to me, feels more intuitive to understand, but you should know that the CDC has separated cases identified in the US and those among the repatriated individuals. Please also remember that these numbers will very likely increase over the coming days.

COVID-19 cases in Europe

As you can see in the table below taken from the World Health Organisation’s most recent situation report, COVID-19 cases have been reported to the WHO from an increasing number of European Region countries. Some key observations include:

Most countries which have reported any cases have reported at least one new case in the previous week.
The majority of European Countries with reported cases are now experiencing local transmission.
Italy (12,442) and France (2,269) continue to have the highest number of reported cases, followed by Spain, Germany, and Switzerland.
Deaths from COVID-19 are primarily concentrated in those same countries.
Ireland has reported its first death.

Description and distribution of COVID-19 cases in the European region, via WHO Situation Report 52 (12 March 2020 20:30 PST)

Finding more information

Government agencies have put up lots of good information that’s available to help you keep yourself and your family safe:

If you’re keen on visualisations (who isn’t?), then you may enjoy these situation dashboards: