What to do when both flu and COVID cases are rising

The cold weather appears to have finally arrived and, in addition to COVID, it’s time to start thinking about the flu. Most people us the term “flu” in a very generic sense, meaning anything from cold symptoms to having a case of vomiting and diarrhea.  The “flu” in this column refers to respiratory influenza.

You are probably aware that last year’s influenza season was incredibly mild (thank goodness). We’re not exactly certain why that was but many hypothesize it was due to all the social distancing, hand washing, decreased travel and mask wearing. Previous flu seasons have been much worse producing between 12,000 and 79,000 annual deaths between 2010 and 2020. Hospitalizations varied between 140,000 and 960,000 and total cases between 9.3 and 49 million.

Influenza is a completely different type of virus than the coronavirus that causes COVID-19. Influenza viruses causing the majority of human infections are classified as Type A or Type B.  Type B usually does not cause severe disease whereas Type A can be lethal, particularly in the young, elderly, and those who have compromised immune systems (much like COVID).

Type A virus can be further characterized into different subtypes or “serotypes” based on which proteins are found on the surface of the virus. When you read about influenza virus with a name like “H3N2,” the “H” and “N” refer to the different proteins on the surface of the virus and the numbers refer to the serotype. The serotypes are also often given common names, usually from their region of origin, such as Influenza A Hong Kong.

Influenza viruses are constantly changing or mutating so that each flu season brings new serotypes. Scientists look at the circulating strains in the southern hemisphere each year and make an educated guess on what serotypes might occur the following year in the northern hemisphere and formulate that year’s vaccine accordingly.

The predominant serotype of influenza A this year looks to be H3N2. This serotype tends to cause more severe disease and was the dominant strain during the severe flu season of 2014-2015. This year’s vaccine is designed to protect us from H3N2, but the circulating strain appears to have resistance to the vaccine. This, combined with our waning immunity from prior influenza infections, could be a recipe for a bad flu season this year.

Despite the apparent poor match this year, vaccination still remains the best defense we have to prevent hospitalizations and deaths. Just like vaccinating for COVID, it’s important to attain a high level of vaccination in a community to reduce the spread of the disease to those who are more likely to die from complications of the disease.

Receiving an influenza vaccine can’t give you influenza. The vaccine is made up of killed virus particles that can’t cause an infection. Some people do have a reaction to the vaccine with some fever and aches, but it is not an infection with the virus. Often people are exposed to cold viruses around the time they receive the vaccine. They come down with cold symptoms, and blame the vaccine for “giving them the flu.” You can receive influenza vaccine at the same time you receive COVID vaccine.

Symptoms of influenza can be similar to COVID and usually include rapid onset, fever (typically 100-103), dry cough, runny nose, chills, headache and body aches. Most people describe it as being hit by a truck. This is in contrast to the common cold that usually has a slow onset, low-grade fever (usually 100 or less), cough, runny nose and mild body aches. Both illnesses usually last around ten days.

Since a virus causes influenza, antibiotics are useless. There are anti-viral medications available to shorten the course of influenza, but they must be started in the first 48 hours of illness to be of any benefit. Many people choose not to take the medication since it is expensive, has some side effects and may only shorten the course by a day or two. The medication can also be administered to high-risk individuals to help prevent infection if they have a high risk of exposure.

While it’s best to contact your health care provider for advice on whether or not to be seen, most healthy people who develop symptoms of influenza usually do not need to see their doctor and should stay home to avoid spreading the infection. People who should see their physician include those with heart or lung conditions and children under the age of two. Those who have diabetes or weak immune systems should also be seen since they are more likely to develop secondary complications of influenza. Shortness of breath and dehydration with severe weakness are also indications to be seen.

Dr. John Roberts is a member of the Franciscan Physician Network specializing in Family Medicine as well as the Deputy County Health Officer in Montgomery County.