With flu season further threatening an already challenging year due to the global COVID-19 pandemic, the Centers for Disease Control is recommending that everyone ages six months and up receive a flu vaccine.
“While it’s not possible to say with certainty what will happen in the fall and winter, CDC believes it’s likely that flu viruses and the virus that causes COVID-19 will both be spreading. In this context, getting a flu vaccine will be more important than ever,” according to the CDC’s website.
To understand the science behind flu vaccines and how it helps minimize infections, SGU News spoke with St. George’s University President Dr. G. Richard Olds, an expert in infectious diseases.
St. George’s University: What are the benefits of getting a flu vaccine?
Dr. Olds: Most of the time the flu vaccine prevents you from getting the flu, and even if it doesn’t, it makes your flu illness less severe and shorter in duration.
SGU: Who should get a flu shot?
Dr. Olds: Everyone should get a flu shot every year. There is almost no downside to getting one, and it clearly helps lessen the severity of the flu. In addition, it keeps us from transmitting flu to vulnerable older adults who are at higher risk from the flu. Thus, the vaccine protects you as well as society.
Importantly, all healthcare professionals are required to get it, so they don’t bring the flu to elderly patients and those with altered immune systems.
SGU: Why is getting a flu shot even more important this year, given the global pandemic?
Dr. Olds: Since COVID-19 symptoms are very similar to flu symptoms—at least in the beginning—getting a flu shot is helpful in avoiding confusion if you develop respiratory symptoms or a fever. It’s important to note that a person can be infected with both flu and COVID at the same time, and it is likely that this double infection will be far worse that either alone.
SGU: How does the vaccine work? Why do some people get “sick” after getting the vaccine?
Dr. Olds: Flu vaccines come in several types. There is a live weakened viral vaccine used primarily for children; there is the killed vaccine, used for many years, primarily for young adults through age 65; and a new high potency vaccine designed for those over 65.
Contrary to popular belief, adults and seniors can’t get the flu from the flu shot given to them. Because we give the flu shot during the fall/winter when many respiratory viruses are around, people often get infected with a non-flu virus around the time they get the flu shot and blame the vaccine for their illness.
That said, children are given a live weakened vaccine that sometimes causes a very mild flu illness. When the child recovers their immune system is ready to fight off the real flu.
SGU: How effective is the flu vaccine?
Dr. Olds: Unlike tetanus shorts or Measles vaccines, the flu virus vaccine must change slightly from year to year in order to work. That’s because the target—the flu virus—mutates rapidly. As a result, the vaccine has to be reformulated every year to match the specific flu virus we expect each flu season. Most years we do a good job of “guessing” what exact flu viruses we will face each fall, but some years the virus mutates in an unpredictable way and the vaccine is not as effective. Even with a mismatch, the vaccine reduces the severity of the illness. Fortunately, we also have antivirals like Tamiflu that we can use to fight flu if a vaccinated person gets infected.
The real problem is that too few people get the vaccine, so the virus circulates effectively and eventually finds the vulnerable members of our society. Very few people would die of flu each year if everyone got a flu shot.
SGU: Can you speak to the speed at which a flu vaccine is created?
Dr. Olds: The entire process takes about four months. Scientists decide what strains they think will circulate in the fall around March and April of each year. Flu shots are usually a combination of three or four specific flu virus strains. Then they have to grow each strain in eggs, harvest the virus, and then formulate the year’s new vaccine. Flu shots first appear in the market in late August or early September.
Since the vaccine is only good for one year (because the virus changes each year), manufacturers try to produce about the same amount of vaccine used the previous year. As a result, if demand going way up, such as this year, we could run out of vaccines before the flu season is over.