Q&A: Coronavirus and Seasonal Flu

An illustration of a coronavirus
Although the coronavirus has commanded headlines, the seasonal flu has killed far more people this year, with flu season barely halfway through. (Getty Images)

The Novel Coronavirus has prompted alarm around the globe, with the U.S. Department of Health and Human Services declaring a public health emergency in regards to the virus. The UConn community has also responded to the reports, highlighting prevention and readiness. At the same time, and receiving far less media attention, the seasonal flu has claimed more than 10,000 lives across the U.S., including at least 23 in Connecticut, with the end of flu season still weeks away. UConn assistant professor in pathobiology and veterinary science Steven Szczepanek says it’s important to study and understand the new coronavirus, but at the same time it’s crucial to not lose sight of the more familiar threat. 


Q: What do we know about the Novel Coronavirus at this point in time?

With the Novel Coronavirus, it seems like there is a lot of cherry picking of information that is being reported and it is important to take note of certain things about infectious disease when looking at statistics about the Novel Coronavirus.

There is something called a “case fatality rate” that has been referenced; currently it is at about 2%. This would mean the Novel Coronavirus is about as virulent as the 1918 “Spanish flu,” which ended up killing 20-50 million people, or about 2-5% of the world population, which is very scary.

But again, this is cherry picking, because sometimes case fatality rate is not a very informative number to use, necessarily.

Q: What goes into calculating the case fatality rate?

Number of cases versus mortality is how you arrive at your case fatality rate.

However, for something like the flu, we can estimate the number of cases that are present in the community that are unaccounted for. There are a lot of people who get the flu and either do not need to see a doctor or who are not tested for some reason.

We can test people for antibodies after an outbreak, and based on that historical data those numbers tend to be far more accurate.

The problem with Novel Coronavirus is that it is too early to do this. We do not know because there are people who are not being tested.

Q: How transmissible is the Novel Coronavirus?

There are some indications showing that Novel Coronavirus is easily transmissible, much like the seasonal flu. This means there could be thousands, perhaps as many as 100,000 cases that have gone unconfirmed. There is substantially more infection than is being reported and when this is considered overall, the mortality rate may drop to 0.2%, which is more in line with the flu mortality rate.

One last thing to further compound the difficulty with calculating case fatality rate, there are not enough test kits for this virus in China. There is very likely far more virus circulating than can even be tested for.

All in all, the numbers being reported are likely substantially underestimated in terms of occurrence for disease, with an overestimated mortality rate.

Q: How does Novel Coronavirus rank with previous pandemic viruses? Should we be worried?

When looking at Novel Coronavirus and others such as MERS, SARS, and the pandemic 2009 Swine flu for instance, there are big differences. MERS had a high mortality rate, but there was a low transmission rate. You will transmit less if you are home really sick. SARS was highly transmissible but easy to trace due to its high mortality and therefore easier to implement quarantine. Swine flu ended up being very similar to seasonal flu in terms of transmission and mortality.

Novel Coronavirus is less virulent than SARS or MERS and is highly transmissible, making it it very difficult to stop. High transmissibility combined with low mortality is still very dangerous.

However, we already have our own endemic virus — the seasonal flu. Novel Coronavirus is definitely something to be concerned with because it seems to behave like the flu.

It is important that people realize this. The seasonal flu is here and it is making people sick and people are dying. The CDC is estimating that so far this flu season there have been 19 million cases in the US with 10,000 deaths and we are just at the start of peak flu season which starts in January and ends in April.

Which virus truly is a threat? It is the one we are all familiar with and the one people tend to not be afraid of.

Q: Do you have any advice for people worried about either virus?

We all have to get annual flu shots because the influenza virus mutates so frequently that it renders our previous immunity just weak enough that the virus can cause infection year after year. Even if you get the flu, if you have had the vaccination, you’re likely to not get as sick.