By: Rachel Levene, Ph.D.
Influenza virus, or the Flu. We’ve all heard about it and we’ve probably even had it a couple of times throughout our lives. Sometimes people tend to refer to all wintertime respiratory illnesses as the flu, but the flu is caused by the influenza virus. Colds and other respiratory illnesses, which can be caused by rhinoviruses, adenoviruses, paramyxoviruses, and even seasonal coronaviruses, are not the same as the flu and tend to result in mild illness. However, the flu can cause severe illness, especially for the elderly, children under 5, and those with pre-existing medical conditions.
Each year influenza causes millions of illnesses, hundreds of thousands of hospitalizations, and tens of thousands of deaths. The best measure we have to prevent illness, hospitalization, and death is the influenza vaccine. Unlike other vaccines given, the influenza vaccine needs to be given each year.
Why does the influenza vaccine need to be given each year? We need to get a flu vaccine each year because the flu virus is constantly changing or mutating. The viral replication machinery that the virus uses to replicate is prone to making mistakes. These mistakes help the virus change, allowing the virus to evade the immune response we mounted from last years’ vaccine. These changes create new strains of the influenza virus. In order to keep up with these changes, scientists update the vaccine to protect against the new strains. It’s like a race – the virus changes in order to get around our immune responses and we change the vaccine to match the new strains.
Why do some years’ vaccines “work” better than others? Despite updating the strains for each years’ vaccine, sometimes there is a mismatch: the strains the vaccine protects against do not match what is circulating in the community. This can happen because the virus underwent more or different changes or mutations that scientists did not predict. When this happens, the vaccine may not prevent against infection and illness altogether. However, recent studies have shown that when vaccinated children do get sick with the flu, they have a milder illness and are much less likely to need hospitalization. The vaccine, even when there is a mismatch, still prevents the worst outcomes from influenza.
Flu Before Boo! Influenza is seasonal – it tends to circulate in the winter months. The best time to be vaccinated is before the winter – ideally before Halloween. Before heading out to trick or treat, be sure to get your Flu Vaccine. This year it’s even more critical to be a Flu Fighter and get a Flu Vaccine to prevent a “twin-demic.” Flu vaccination (and COVID-19 vaccination if 12 and older) could prevent infection and severe illness from infection with both viruses at the same time. Additionally, high rates of flu vaccination can keep influenza from spreading in communities and can help keep hospitalizations down, which is especially critical with the Delta variant of COVID-19 surging. Hospitals overwhelmed with influenza and COVID-19 patients beyond their capacity can lead to rationing of care and potentially limited staff, supplies, and beds to care for patients with other medical needs such as car accidents, broken bones, cancer surgeries and treatment, strokes, heart attacks, appendicitis, etc.
Vaccines save lives!