As COVID occupied our news feeds over the last year, many may have forgotten about the other respiratory illness that is always on our mind during the winter – the flu. Cases of the flu this year have been at shocking lows since COVID distancing and masking measures have proved effective in curbing other respiratory illnesses as well. However, we all have to be prepared for this winter’s flu season that will allow the flu to make a comeback in the absence of COVID protocols. The question is: how big of a comeback with the flu make?
Fast Facts about the Flu
To start, a little bit about the flu. Like COVID, the flu is a respiratory disease with symptoms of fever, fatigue, a sore throat, runny nose, and aches. Unlike COVID, though, there is usually no loss of taste or smell associated with having the flu. It is transmitted through liquid droplets that transfer from one person to another when talking, breathing, coughing, or sneezing within a distance of 6 feet (also like COVID!) and those who have the flu are most contagious 3-4 days after symptoms begin.
The flu season typically runs from December to February with a two-month buffer on either end of that range. Ideally, people should start getting vaccinated for the flu in October but 50% of all Americans don’t get vaccinated. The flu can be treated through at-home remedies or through the use of antiviral medications that prevent the virus from infecting any more of the body than it already has rather than “killing the virus” as an antibiotic would do to a bacteria.
Both the flu and COVID can have serious consequences on one’s organ system. In the lungs, they can cause pneumonia, respiratory failure, or the build-up of fluids. They can also cause sepsis (a body’s response to an infection that destroys its own tissues too), cardiac injury, and inflammation of the heart, muscles, and brain. In the rare case that someone gets infected by COVID and the flu simultaneously, this could substantially increase the long-term effects on these various organs affected by the infections. This double infection would also double the risk of dying than COVID alone.
Pandemic curbed Flu Rates
Many COVID protocols including frequent sanitation, hand washing, and distancing and masking measures that prevent the transmission of aerosol droplets have helped decrease flu rates this season. As seen below, flu rates are down in all parts of the world as a result.
The decrease in flu cases this 2020-2021 season is clear in various parts of the world.
- In the UK, flu cases are down 95% this season.
- Deaths caused by the flu in England and Wales (2/4 parts of the UK) are down from 26,938 to 15,437 as of 2020 (when pandemic restrictions started) when compared to 2019.
- In Hong Kong, flu transmission decreased by 45% due to pandemic restrictions.
- RSV (a respiratory virus that typically affects children) and flu rates in Australia have decreased by 98% in children.
- In America, flu cases were down from 38 million last season to just 2,038 reported cases as of the start of this season to April.
Though this decrease in the flu over the last year has helped healthcare professionals focus on COVID instead of overwhelming them with two respiratory disease outbreaks, the same cannot be said for the upcoming season. As pandemic restrictions drop the flu will be returning and possibly at a greater rate. Why? Immunity from the flu achieved by vaccination or previous exposure decreases over time since antibodies become weaker. For the large number of people who didn’t get the flu vaccine last year, their immunity solely depends on exposure to the flu two seasons ago, which is likely not much.
Additionally, flu vaccines are not as potent as COVID vaccines, with only a 50% effectiveness rate. There are over 4 types of flu (A-D) and numerous subtypes. Typically, type A and B are responsible for the seasonal flu. Within type A there are numerous subtypes identified hemagglutinin and neuraminidase surface protein markers. Type B only has two subtypes, the Yamagata and Victoria lineages. Of all these subtypes, the flu vaccines usually only protect against 4 subtypes, making the vaccine a sort of “insurance” rather than a cure.
This doesn’t mean that getting the flu vaccine is not important. In fact, now more than ever it is important to get the vaccine to prevent overwhelming healthcare professionals when COVID cases also grow in the winter. Getting the flu will also weaken your immune system, making you more prone to a serious COVID infection if exposed and vice versa (COVID will increase vulnerability to flu).
Also, even if you do get the flu after being vaccinated, the symptoms are typically less severe. A large percentage of people who get the flu are typically unvaccinated, so the vaccine is still an effective prevention measure for most people. It is also important to note that getting the vaccine annually is important since the vaccine is modified to provide immunity to newer strains of the flu each year and immunity from the vaccine decreases over time.
How the Flu will Reemerge
Tracking the RSV virus – another respiratory virus- has helped predict many of the flu trends that I have discussed. RSV rates have recently been increasing since many kids have been going back to daycares and schools unlike adults and RSV typically only affects kids. Since many adults are still working from home and it is still summer, opportunities for flu breakouts are low as of now. However, the growth in RSV cases predicts a likely growth in flu cases when more people return to offices and winter comes around.
When considering flu variants, many of them have also been wiped out or reduced to small numbers during the pandemic due to distancing measures, such as the Type B Yamagata line. However, they could begin to reappear this flu season as the virus circulates more and increases its genetic diversity, increasing the transmissibility of the flu.
Additionally, it is likely that the more robust variants of the flu that are more transmissible and better at evading antibodies are the only ones currently circulating. This means that when flu season does come around and these variants spread and mutate, even more, there is a good chance that infection rates will be high in comparison to if the “less harmful” variants were also around.
It is safe to say that this year the flu will most likely make a pretty strong comeback if COVID restrictions continue to be lifted. Continuing sanitation protocols and mask-wearing in crowded settings may be wise on both an individual and large-scale basis. Please also make sure to get the flu vaccine (and the COVID one of course) to protect yourself and others around you as much as possible. From a personal perspective, getting the flu is a nasty experience and you don’t want to be bedridden for 5 days drinking nothing but soup. The flu doesn’t have to stick around this year either if we can keep some good habits and get vaccinated!