COVID-19 Frequently Asked Questions

last updated March 6, 2020

As a team, we’re fielding a lot of questions about COVID-19 and how individuals and families should be preparing. We compiled a list of the most common question. In this document we answer them with information and recommendations from resources that we trust.

It is important to note that COVID-19 is a novel virus; We are still learning about disease characteristics including who is most likely to become infected or experience serious illness as a result of it. Current clinical knowledge is based primarily on data from the China outbreak. We believe everyone should be taking steps to protect themselves and their families. We hope the resources below will help you to do that.

What can be done to prevent or reduce the spread of COVID-19?

COVID-19 is a respiratory virus, and nonpharmaceutical interventions are the most effective tool we currently have to prevent and slow the spread of COVID-19 at this time. There is not currently a vaccine or specific treatment for COVID-19. Some key ways to implement nonpharmaceutical interventions are to:

  • Practice social distancing, such as limiting attendance at events with large groups of people
  • Stay home, especially if you are feeling ill
  • Implement good hand washing practices - it is extremely important to wash your hands regularly and thoroughly (see below for how-tos!)
  • Cover coughs and sneezes with your elbow or tissue
  • Avoid touching your eyes, nose, and mouth with unwashed hands
  • Disinfect frequently touched surfaces, such as doorknobs
  • Begin to take your temperature every day, if you develop a fever, stay home (if possible, separated from other people you live with) and call your doctor
  • Start preparations in anticipation of social distancing and potential supply chain shortages. This includes ensuring you have sufficient supplies of prescription medicine and have about a 2-week supply of food and other necessary household goods
  • If possible, discuss a plan to work from home with your employer or how classes could be attended remotely

With these steps in mind, it is important to not panic and panic buy. Panic buying unnecessarily increases strain on supply chains and can make it difficult to ensure that everyone is able to get supplies that they need. For an excellent explanation on why we should all be having a proactive, but measured response to the situation, we recommend reading this twitter thread by Nextstrain team member, Emma Hodcroft, PhD.

Some other resources and articles we have found extremely useful during our own preparations are:

Past Time to Tell the Public: “It Will Probably Go Pandemic, and We Should All Prepare Now” by Jody Lanard and Peter M. Sandman

Ready - Pandemic Preparedness Page - a helpful public service campaign on disaster preparedness from the US Department of Homeland Security

So you think you’re about to be in a pandemic? by Ian McKay, PhD and Katherine E Arden, PhD

US CDC - Preventing COVID-19 Spread in Communities

US CDC - When & How to Wash Your Hands

US CDC - Nonpharmaceutical Interventions

US CDC - What to Do if You are Sick

US CDC - Coronavirus Disease 2019 (COVID-19)

How is COVID-19 spread?

COVID-19 is a respiratory virus, which spread in 3 main ways:

  1. Between people who are in close contact with each other (within about 6 feet, or 2 metres), through small aerosolized particles that can be produced when a person talks, coughs, or sneezes.
  2. In (relatively) larger droplets that are produced someone coughs or sneezes (these can travel over similar distances).
  3. Contact with surfaces or objects infected with the virus (also known as fomites). If a person touches an infected surface and then touches their eyes, nose, or mouth without washing their hands, they may become sick by introducing the virus into their body.

For COVID-19 there is evidence of transmission in clinically mild and asymptomatic cases. This means that people who are infected with COVID-19 and able to transmit the virus to others may not appear, or even feel, sick.

Though there is not yet clear evidence on how long the COVID-19 virus can survive on surfaces, we expect it to be similar to other coronaviruses. Coronaviruses can live on surfaces for anywhere from a couple hours to several days, depending on the surface and the climate. The US CDC recommends disinfecting frequently touched areas often.

How quickly is COVID-19 spreading?

Based on disease modeling estimates and phylodynamic analysis, the current epidemic doubling time is about 7 days. There is uncertainty with these estimates and this rate will vary based on community contact patterns. Nonpharmaceutical interventions can be effective in reducing this rate, as we have seen in China. Sudden jumps in case counts are likely due to increases in testing capacity catching cases that were previously missed by surveillance systems.

Current case counts, deaths, and recoveries are being tracked in a number of places. These are updated as regularly as possible, but may not always be immediately up to date. One dashboard that we particularly like is from the Johns Hopkins Center for Systems Science and Engineering:

Johns Hopkins CSSE Dashboard

Who is at the highest risk for COVID-19?

Studies of patients in China have shown that most COVID-19 cases are adults. Just 2.1% of 44,672 cases in China were in individuals below 20 years of age and just 1% of those were in children under 10 years of age. Approximately 80% of people experience mild illness, 14% experience severe disease, and 5% experience critical illness (meaning the patient experienced respiratory failure requiring mechanical ventilation, shock, or other organ failure that required intensive care). Overall, 20% of Chinese cases required hospitalization.

The WHO currently estimates the overall case-fatality rate at 3.4%, but says that it can range from 0.7% to 4% depending on the quality of the healthcare system where the case is treated. Based on data from China, the case-fatality rate was 14.8% in patients aged ≥80 year, 8.0% in patients aged 70-79 years, and 49.0% in critical cases. The WHO-China CDC Joint Report found that while women and men were infected at similar rates, COVID-19 infections seem to be more severe in men. Only 2.8% of Chinese women who were infected died from the disease, while 4.7% of infected men died.

Based on the WHO-China CDC Joint Report, individuals over 60 and those who have weakened immune systems or underlying health conditions like hypertension, diabetes, cardiovascular disease, chronic respiratory disease and cancer are at a higher risk for severe disease.

Children do not seem to be at a high risk for either contracting COVID-19 or having severe disease as a result of an infection. A great graphic by Jesse Bloom, PhD and his team illustrates this point and compares case fatality across age groups; it be viewed here. Additionally, we’d recommend looking at this graphic from Claus Wilke, PhD, which re-plots the same data on a log-scale and highlights that, with the exception of children, COVID-19 is consistently worse than the seasonal flu, across all age groups. With both these graphics, it’s important to note that all statistics are subject to error and biases, but these do give a ballpark idea of the risk of COVID-19 among different age groups.

At this time, little evidence exists on the risk of COVID-19 to pregnant women, fetuses, and newborns. More detailed information on this can be found on the US CDC’s page, Coronavirus Disease 2019 (COVID-19): Pregnant Women. That being said, Public Health — Seattle King & County (the local public health authority in Seattle, WA where many of our team members are based) has recommended that pregnant women and membesr of other high risk groups stay home and away from larger groups of people as much as possible.

More detailed information on outcomes and clinical characteristics can be found in the original journal article summarizing the WHO-CHina Joint Mission Report and the report itself: Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China by Zunyou Wu, MD, PhD and Jennifer M. McGoogan, PhD.

Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19O).

What are the symptoms of COVID-19?

Based on the data from China, the most commonly reported symptoms are fever (88%), dry cough (68%), exhaustion (38%), wet cough (33%) and shortness of breath (18%). About 14% of people also experience sore throat, headaches, and muscle aches. Again, these symptoms will be mild in about 80% of cases. COVID-19 is a lower respiratory infection (so most symptoms will appear “below” the voicebox) but is a flu-like illness and how its symptoms present varies from person to person. If you are concerned about symptoms you or someone else may be having, in line with US CDC recommendations, we suggest calling your doctor or local health department to discuss next steps.

More detailed information on outcomes and clinical characteristics can be found in the original journal article summarizing the WHO-CHina Joint Mission Report and the report itself: Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China by Zunyou Wu, MD, PhD and Jennifer M. McGoogan, PhD.

Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19O).

What should you do if you think you might be sick with COVID-19?

At the time of publication, the US CDC recommends to “Call ahead to a healthcare professional if you develop a fever and symptoms of respiratory illness, such as cough or difficulty breathing, and have been in close contact with a person known to have COVID-19 or if you live in or have recently traveled to an area with ongoing spread. Tell your healthcare professional about your recent travel or contact. Your healthcare professional will work with your state’s public health department and CDC to determine if you need to be tested for COVID-19.”

For more detailed information on what to do if you are concerned that you or someone you know might have COVID-19, please review the US CDC page, What to Do if You are Sick. This page includes information for individuals who may be sick, as well as information for their family members, caregivers, and intimate partners.

Is it safe to travel?

At the time of publication, the US CDC has “established geographic risk-stratification criteria for the purpose of issuing travel health notices for countries with COVID-19 transmission and guiding public health management decisions for people with potential travel-related exposures to COVID-19.” A listing of risk assessments for different countries and what this means for traveler’s can be found on the US CDC’s Coronavirus Disease 2019 (COVID-19): Travel Information page.

What are coronaviruses, SARS-CoV-2, and COVID-19?

Coronaviruses (CoV) are members of a diverse species of positive-sense single-stranded RNA ((+)ssRNA) viruses which have a history of causing respiratory infections in humans. Some variants of coronaviruses are associated with outbreaks, others are continuously circulating and cause mostly mild respiratory infections (e.g. the common cold). Their name comes from the Latin word for crown or halo, Corona, which references the club-shaped protein spikes that the surface of coronaviruses are covered in. More information about coronaviruses can be found on our Human Coronavirus page.

SARS-CoV-2 is the specific coronavirus that causes Coronavirus Disease 2019, which is abbreviated to COVID-19. SARS-CoV-2 is the cause of the ongoing COVID-19 outbreak. A bit more about SARS-CoV-2 can be found on our SARS-CoV-2 page.

What is the origin of the COVID-19 virus?

The origin of the virus is still unclear, however genomic analysis suggests the COVID-19 virus is most closely related to viruses previously identified in bats. It is plausible that there were other intermediate animal transmissions before the introduction into humans.

There is not evidence of snakes as an intermediary. A good, though technical, explanation of why there is not evidence of snakes as an intermediary was written by Kristian Andersen, PhD, at the Scripps Research Institute. This article was posted on Virological and can be found here.

There is not evidence that the COVID-19 outbreak is the result of a lab escape. The data we have on the COVID-19 outbreak is consistent with a zoonotic origin and inconsistent with a lab escape scenaria (where a virus being used for research “escapes” from the laboratory and causes an outbreak). The WHO-China Joint Report noted that “since the COVID-19 virus has a genome identity of 96% to a bat SARS-like coronavirus and 86%-92% to a pangolin SARS-like coronavirus, an animal source for COVID-19 is highly likely.” For a full analysis of the evidence supporting a zoonotic origin over a lab escape origin, please read this twitter thread by Nextstrain team member, Trevor Bedford, PhD, which discusses this issue in-depth.

There is not evidence that the COVID-19 virus was genetically engineered with HIV sequences. This theory was based on a pre-print paper that has since been thoroughly debunked and the article has been withdrawn. A non-technical discussion of why this theory had no ground can be found in this article in Forbes, which links out to Nextstrain team member, Trevor Bedford’s, twitter thread on the same topic.

For a less technical discussion of why the COVID-19 outbreak is not the result of a lab escape and why the virus was not genetically engineered, we recommend this VOX article, which discusses both points.

Is one strain of the COVID-19 virus more severe?

There is not evidence that any strain of the COVID-19 virus, SARS-CoV-2, is more severe. A recent paper has claimed that SARS-CoV-2 has split into two strains, “L” and “S”, with the “L” strain causing a more severe version of COVID-19. This theory was used to try to explain the higher case fatality ratio that has been seen in Wuhan, China, the epicenter of the outbreak as compared to other parts of China. Nextstrain team member, Richard Neher, PhD, summed up why this theory is inaccurate in this twitter thread. In short, this difference in case fatality rates is likely a statistical artifact due to the way that “genomes are sampled extremely heterogeneously in time and space. Rapidly growing local outbreaks get sampled intensively and result in overrepresentation of some variants.”

A more detailed discussion of why there is not evidence for this claim was written by posted on Virological by Oscar A. MacLean et al., at the MRC-University of Glasgow Centre for Virus Research.

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All source code is freely available under the terms of the GNU Affero General Public License. Screenshots may be used under a CC-BY-4.0 license and attribution to must be provided.

This work is made possible by the open sharing of genetic data by research groups from all over the world. We gratefully acknowledge their contributions. Special thanks to Kristian Andersen, David Blazes, Peter Bogner, Matt Cotten, Ana Crisan, Gytis Dudas, Vivien Dugan, Karl Erlandson, Nuno Faria, Jennifer Gardy, Becky Kondor, Dylan George, Ian Goodfellow, Betz Halloran, Christian Happi, Jeff Joy, Paul Kellam, Philippe Lemey, Nick Loman, Sebastian Maurer-Stroh, Oliver Pybus, Andrew Rambaut, Colin Russell, Pardis Sabeti, Katherine Siddle, Kristof Theys, Dave Wentworth, Shirlee Wohl and Nathan Yozwiak for comments, suggestions and data sharing.


© 2015-2020 Trevor Bedford and Richard Neher