Rutgers infectious disease expert explains the importance of flu vaccinations this fall

While social distancing and wearing masks kept last year’s flu season at an all-time low, experts expect flu cases will soar this year as students return to school and employees go back to the office and are urging people to get their flu vaccine to prevent the nation’s health care system from being overwhelmed by influenza and COVID-19.

David Cennimo, an infectious disease expert at Rutgers New Jersey Medical School, discusses what you should do to protect yourself during the upcoming flu season.

What can we learn from last flu season and what should we expect this year?
The low case numbers show that COVID-19 mitigation measures such as wearing face masks, staying home, hand washing, school closures, reduced travel, increased ventilation of indoor spaces and physical distancing worked. Preliminary estimates indicate that up to 55 percent of adults got a flu vaccine last year, up from about 48 percent before the pandemic. Pediatric deaths fell from 199 children in the 2019–20 flu season to only one death this year. This should be an object lesson that increased vaccination rates and mitigation measures can be successful.

Based on what we are currently seeing for other respiratory infections, like respiratory syncytial virus, which is coming back with a vengeance, I expect we will see a resurgence of influenza at above-average levels this year.

When is the optimal time to get a flu shot?
The CDC recommends that people age 6 months or older receive flu vaccinations by late October although getting a vaccination later can still be beneficial, and I would not discourage vaccination in September. The vaccine is effective for about six months. If you get vaccinated too early and we have a late peak in March, your immunity might wane. Certain children may need a booster shot after the initial vaccination; check with your doctor.

If needles make you uneasy, the nasal mist vaccine is an effective alternative for people between age 2 to 49 with normal immune systems. It is not for pregnant women, children receiving aspirin or asthmatics under age 4.

Do COVID-19 and flu shots need to be spaced out?
No. The CDC originally recommended a two-week spacing between COVID-19 and other vaccinations, since it was closely monitoring reactions for this new vaccine. This is no longer the case. If you are in your doctor’s office for a COVID-19 shot, you can get your flu vaccination at the same time.

Is a twin-demic—simultaneous COVID-19 and flu outbreaks—possible this year?
It’s very possible, and it’s another reason why flu and COVID-19 vaccinations are so important. Although instances have been rare, you can contract COVID-19 and the flu simultaneously, which could result in a much worse condition. On the health care side, having both viruses circulating makes diagnosis difficult. If you contract the flu, you will have to quarantine and be tested to rule out COVID-19. This highlights the importance of children under 12, who cannot yet receive the COVID-19 vaccine, receiving the flu vaccine. Vaccinated children are less at risk for the flu, whose symptoms can be confused with COVID-19 and cause possibly unnecessary school quarantines while awaiting a proper diagnosis.

How are the coronavirus and the flu similar and different?
Both spread predominantly through respiratory droplets and contact. There seem to be more asymptomatic cases of coronavirus than influenza, but both are capable of being spread before a person knows they are infected – about one to two days before any symptoms appear. Influenza contagiousness is usually over within a week while coronavirus is around 10 days. Both can cause a spectrum of illness ranging from mild to critical illness and death.

Who is especially vulnerable for contracting the flu?
Everyone 6 months of age or older should be vaccinated, but it is especially important for those who are at higher risk for complications and mortality. The CDC estimates that 70 percent to 90 percent of annual flu deaths are in people over 65. People with chronic conditions, like heart disease, fare worse when they have the flu and can suffer heart attacks. Vaccination is also critical for caretakers and essential workers who are more likely to transmit the virus if not vaccinated.

Pregnant women should receive the flu shot because they have a high risk of severe symptoms and to help confer some immunity to their newborns.

Black, Hispanic and American Indian or Alaska Natives people also had significantly higher rates of hospitalization and intensive care unit admission for the flu, according to a recent study. Because these racial and ethnic minority groups might be at higher risk for developing serious illness, flu vaccination is especially important. COVID-19 data have also shown that socioeconomic status plays a part in exposure risk because some jobs cannot be done from home or and some workers cannot sequester in a private office to prevent contagion. 

Are influenza vaccines safe?
Vaccines are the most extensively tested entity in medicine and adverse effects are vanishingly small. Extremely rare side effects – like allergic reaction – can happen, but the risk is still lower than with many other common medications and surveillance platforms that look for possible adverse effects are ongoing.

Unless someone with an egg allergy has had an allergic reaction to the flu vaccine in the past, they should get the vaccine. If their allergy is serious, they should be monitored while taking the shot. Also, there are two vaccines not made in eggs: rIIV, a recombinant protein, and ccIIV, which is made in cell culture.

Can you get the flu from the flu vaccine?
The vaccine takes two weeks to be effective, so people still could contract the flu during this period. The vaccine exposes your body to a weakened form of the virus, which allows you to mount an immune response. ​So, essentially you are getting a “mini-flu” illness, which is why some people may feel ill after getting the vaccine.

How can one person’s vaccination possibly save lives?
As we have seen with COVID-19, people can have the flu, not realize it and gravely affect someone vulnerable, like the elderly, children and those who have an impaired immune system, such as cancer patients undergoing chemotherapy and people with HIV or pulmonary disease. Not only will getting a flu shot reduce your odds of getting sick, it also means that if you do contract the flu, your illness would be less severe.