Impressive data from coronavirus vaccine trials led by Pfizer (NYSE:PFE) and Moderna (NASDAQ:MRNA), inspired much hope around the world and injected optimism into the stock market. But the flu season is still in full swing and people need to be vigilant in keeping themselves safe.

The Motley Fool sat down with Dr. Jeremy Brown, author of Influenza: The Hundred-Year Hunt To Cure The Deadliest Disease In History and Director of Emergency Care Research at the National Institutes of Health. Dr. Brown shared lessons from the 1918 influenza pandemic that are still relevant today.


Corinne Cardina: I'd like to get a little bit more general now, I want to hear about influenza. You, of course, did an insane amount of research for your book about influenza. I'm curious, what is still relevant for today's pandemic that you've learned 100 years after the influenza pandemic?

Dr. Jeremy Brown: Well, as you said, I wrote this book in influenza that came out two years ago now, seems like forever or two years ago in 2018, which the 100th anniversary of the great influenza pandemic of 1918. I looked at what had happened over the last 100 years. I did tell the story of what happened in 1918, which is very sobering of course. Fifty to one hundred million people died across the world, 675,000 people in the United States died, which is the equivalent in today's population of about three million. So it was far more deadly, at least in terms of numbers than the COVID pandemic is so far. Let's hope that COVID pandemic does not catch up to that awful number of deaths in the US and across the world. But influenza does remain, of course a perennial challenge for us. We are still trying to find that vaccine that can be given once and once only that will cover all different types of influenza virus, all the different viruses, across the world they differ from each other. So you can get a vaccine that's given once, it'll be good against all the different kinds of the virus and it will last for many years. Just given a vaccine each year is a problem because people have to remember and they have to come back. If we can have a vaccine that will give us the long-term protection that for instance, the MMR, Mumps, Measles, Rubella vaccine gives us that would be an incredible breakthrough as well. We don't have that yet, with the influenza vaccine. Influenza each year in the United States kills anywhere between 12,000 and over 100,000 people each year. We don't have good statistics about it simply because it's very difficult for everybody to agree on whether a death is caused by influenza or secondary pneumonia from influenza or heart failure caused by influenza in older people and younger people. It's unfortunately easier to decide that this was a death directly from influenza. So we have a very wide range of estimation of the number of people who died. Certainly, the very beginning of the outbreak of COVID people were mourning. I think I was one of them as well. We said, look, so far, this was in January time, the enemy is influenza rather than COVID. Now of course, we know that that changed very quickly. But influenza certainly remains a challenge for all of us. What I am hopeful for is that because of the precautions that all of us are or should be taking with mask and hand washing and social distancing, that the influenza numbers actually will be way lower than they are in a normal year. We would expect that because influenza is passed in much the same way as COVID is passed on droplets. If you're not in the office or on the bus or on the subway being sneezed on by other people who have it, then you're less likely to get it. So one would expect that when the dust settles and we're able to look back at the flu season last year initially, we will actually see a decrease in the number of deaths from influenza. That of course, will again remind us that every year we need to be taking these precautions, COVID will go away eventually, either through a vaccine or through the natural process, all pandemics come to an end. The question is how much damage they can cause while they are active. But when COVID has gone away, I think that we will be able to learn and remind ourselves that just taking these very basic precautions, it's not only good for reducing the risk of COVID, but it's also a very good way to stay healthy over the winter to more flu and other winter viruses. Couple of wonderful studies that were done in which kindergarten children were put into different groups. One class would wash their hand several times a day and the other class would not be told to wash their hand several times a day just as needed. When you compare the two different groups, of course, the kindergartners who washed their hand several times a day had a much lower absentee rate because of virus infections and so on. That's just a little morsel that remind us these very basic precautions that we're all now taking are good, not only for COVID, but for all of the winter viruses.

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