October traditionally marks the beginning of flu season. In recent years, the flu season has extended well into the next year. Multiple strains of human influenza virus were already detected in October—Louisiana and Puerto Rico are early U.S. hot spots for the 2019-2020 season.

My advice is to be prepared and get that flu shot right away in the northern hemisphere. I can personally recommend this because my St. Jude colleagues and I actually help to decide what goes into the world’s flu vaccines (more on that below).

I do not take it personally that only half of Americans get the flu shot each year, nor do I hesitate to vigorously debunk common myths and excuses that I hear every year. Here are the top four excuses:

“Why? I never get the flu!” That is only good luck, and it’s just as likely that you’ve actually caught a mild case without feeling any symptoms. You can spread influenza to less fortunate people if you are infected, even if you feel great.

“Not yet! I want my vaccine to last to the end of the season,” followed by “I forgot, and now it’s probably too late!” There is no need to strategically delay your vaccination, which puts you at risk of getting infected before you get the shot. Remember that once you receive the shot, it takes another two weeks for the antibodies to build up. But as long as influenza is circulating, it is not too late to get vaccinated. Flu season can last as late as May in the northern hemisphere.

“I had the shot and I still caught the flu!” I admit we don’t always get the vaccine exactly right and it doesn’t protect everyone all of the time. Each year’s vaccine activates your immune system against three or four circulating flu strains. But some types of flu currently lack optimally effective vaccines, despite our best efforts. Sometimes part of the vaccine mutates during its months-long development cycle and no longer matches one of its target viruses. You also may have caught something similar to influenza, such as a severe cold, pneumonia or bronchitis. The flu shot doesn’t protect against those.

“The vaccine can cause the flu.” No, it cannot. Injected flu vaccines only contain inactivated (killed) viruses or proteins taken from viruses. We could say that a tortilla chip is “inactivated corn.” It’s made from corn seeds, but you can’t plant a chip to grow a corn plant. If you feel side effects during the week following a flu shot, that is probably your body cranking up an immune response, setting up an ambush against infection.

Even if the shot doesn’t prevent you from getting sick, it can still lessen the length and severity of your flu infection. The vaccine also protects you from developing complications such as pneumonia. In fact, the Centers for Disease Control and Prevention (CDC) reported that the 2016-2017 flu vaccine likely prevented 5.3 million illnesses, 2.6 million associated medical visits and 85,000 hospitalizations.

Your vaccination protects other people, too

Please remember that the flu vaccine isn’t just about you. With that vaccine in your system, you become one less walking, talking, exhaling vector for spreading influenza. Think about people around you who are most at-risk — the elderly, children and people with chronic health problems. Heart disease patients infected with flu are especially vulnerable to pneumonia and other life-threatening respiratory conditions.

Why is St. Jude studying influenza?

Here at St. Jude, the flu can have devastating effects on our young patients when their immune systems are weakened by cancer treatments. The Department of Infectious Disease has been researching influenza and its epidemics since 1968. We have been a designated World Health Organization (WHO) Collaborating Center since 1975, one of six such centers operating under the WHO Global Influenza Surveillance and Response System (GISRS).

Our role in WHO influenza programs is focused on the threat to humans from animal viruses. And that is how we came to be part of the small circle of GISRS member institutions who directly advise WHO, and the world, on vaccine formulations.

A ‘security council’ against influenza

This circle of immunologists and virologists meets in September to recommend a vaccine package for the southern hemisphere and each February to plan for the northern hemisphere’s next flu season. It’s somewhat like a United Nations Security Council for fighting influenza. In fact, our regular meeting place, at WHO headquarters in Geneva, resembles the Security Council chamber, complete with a large, ring-shaped table.

We ask a pretty simple question at each advisory meeting: Are the latest flu strains collected from the field—and the viruses we think will be the dominant strains in the next flu season—similar to current vaccine strains? Have any shifted antigenically away from the vaccine strains? The answer determines which strains are added to or removed from the vaccine.

The nine advisors include representatives from the WHO Collaborating Centers and Essential Regulatory Laboratories:

  • Francis Crick Institute, London
  • Centers for Disease Control and Prevention, Atlanta
  • St. Jude Children’s Research Hospital, Memphis
  • National Institute of Infectious Diseases, Tokyo
  • Chinese National Influenza Center, Beijing
  • Peter Doherty Institute for Infection & Immunity, Melbourne
  • U.S. Food and Drug Administration
  • Australian Therapeutic Goods Administration
  • U.K. National Institute for Biological Standards and Control

From there, our recommendations are evaluated by various national vaccine regulatory agencies and the pharmaceutical manufacturers to produce and license influenza vaccines in time for the next flu season.

And that’s where you come in. You come in to a clinic or pharmacy, bare your shoulder, and help us all fight influenza.