MEAWW.COM / NEWS / HEALTH

Is the flu vaccine safe? CDC says it prevented 7.5M illnesses and 6,300 deaths last season

It takes about two weeks after vaccination for flu antibodies to develop, so the agency recommends that people get a flu vaccine by the end of October for the best protection

Flu vaccine prevents millions of illnesses, flu-related doctor visits, hospitalizations, and deaths each year, and that is why the US Centers for Disease Control and Prevention (CDC) recommends that all Americans, 6 months and older, should get a flu shot every season. Due to the Covid-19 pandemic, reducing the spread of respiratory illnesses, like flu, this year are more important than ever, say experts. The CDC believes it is likely that flu viruses and the virus that causes Covid-19 will both be spreading in the fall and winter. Since hospitals and doctors are going to be very busy caring for Covid-19 patients, a flu vaccine can help decrease the burden on the healthcare system and make sure that those who need medical care can get it.

What do the numbers say?

According to CDC estimates, influenza vaccination prevented an estimated 7.52 million illnesses, more than the combined population of Kentucky and Kansas, 3.69 million medical visits, as well as 105,000 hospitalizations due to flu during the 2019-2020 season. Vaccination also prevented 6,300 deaths due to influenza during the 2019-2020 season, equivalent to saving about 17 lives per day over a year. “This report underscores the benefits of the current vaccination program but highlights areas where improvements in vaccine uptake and vaccine effectiveness could deliver even greater benefits to the public’s health,” write authors. 

The number and proportion of flu-associated hospitalizations prevented by vaccination during 2019-2020 varied by age group, due to age-specific differences in influenza burden, vaccine coverage, and vaccine effectiveness. Vaccination prevented the lowest proportion of illnesses among adults aged 18 to 49 years, the age group in which vaccination coverage is lowest, and among children aged 5-17 years, for whom vaccine effectiveness was low for both influenza B and influenza A(H1N1)pdm09 viruses. Vaccination prevented the greatest proportion of outcomes among children aged 6 months to 4 years, an age group in which there was high vaccine uptake, and the vaccine effectiveness was greatest.

Among other research, during 2018-2019, vaccination prevented an estimated 4.4 million influenza illnesses, 2.3 million flu-associated medical visits, 58,000 influenza-associated hospitalizations, and 3,500 flu-associated deaths. A 2018 study reveals that from 2012 to 2015, flu vaccination among adults reduced the risk of being admitted to an intensive care unit (ICU) with flu by 82%. 

Key preventive tool for people with chronic health conditions

Vaccination is particularly important for people at high risk of serious complications from influenza. Flu vaccination has been associated with lower rates of cardiac events among people with heart disease, especially among those who had had a cardiac event in the past year. Vaccination can also reduce worsening and hospitalization for flu-related chronic lung disease, such as in persons with chronic obstructive pulmonary disease. According to the CDC, flu vaccination has been shown in separate studies to be associated with reduced hospitalizations among people with diabetes and chronic lung disease.

Helps protect women during and after pregnancy

As per the CDC, Vaccination reduces the risk of flu-associated acute respiratory infection in pregnant women by about one-half. A 2018 study that included influenza seasons from 2010-2016 showed that getting a flu shot reduced a pregnant woman’s risk of being hospitalized with flu by an average of 40%. Several studies have shown that in addition to helping to protect pregnant women, a flu vaccine given during pregnancy helps protect the baby from flu for several months after birth when he or she is not old enough to be vaccinated.

Reduces illness severity 

While some people who get vaccinated still get sick, flu vaccination has been shown in several studies to reduce the severity of illness. Flu vaccination reduced deaths, intensive care unit (ICU) admissions, ICU length of stay, and overall duration of hospitalization among hospitalized flu patients, reveals a 2017 study. It concludes that unvaccinated hospitalized flu patients were 2 to 5 times more likely to die than someone who had been vaccinated. In another report, among adults hospitalized with flu, researchers found that vaccinated patients were 59% less likely to be admitted to the ICU than those who had not been vaccinated. Among adults in the ICU with flu, vaccinated patients on average spent four fewer days in the hospital than those who were not vaccinated.

Flu shot can be lifesaving for children

Flu vaccination can significantly reduce a child’s risk of dying from flu. A 2017 study found that flu vaccination reduced the risk of flu-associated death by half (51%) among children with underlying high-risk medical conditions and by nearly two-thirds (65%) among healthy children. 

According to a recent analysis, even in a season where vaccine components were not well-matched, flu vaccination prevented moderate to severe illness in children. During the 2018-2019 flu season, flu vaccinations reduced hospitalizations by 41%, and emergency department visits by 51% even though vaccines were not well matched with one of the circulating viruses. Vaccine effectiveness increased to 61% against ED visits related to the A(H1N1)pdm09 strain of the flu, which was initially predominant during the 2018-19 season. “The 2018–2019 influenza vaccine reduced pediatric influenza A-associated hospitalizations and ED visits by 40% to 60%, despite circulation of a drifted A(H3N2) clade,” the authors concludes. 

How else can people protect themselves?

Getting a flu vaccine each year is the best way to prevent the flu. Apart from that, the CDC suggests that people should take everyday preventive actions to prevent the spread of flu, including covering coughs, washing hands often, staying home when they are sick, and avoiding people who are sick. Antiviral drugs are an important second line of defense to treat the flu, but the agency cautions that they are not a substitute for vaccination and must be prescribed by a healthcare provider. 

When should I get vaccinated?

Health experts recommend that people should get a flu vaccine before flu viruses begin spreading in the community since it takes about two weeks after vaccination for antibodies to develop in the body and provide protection against flu. The CDC advises that people get a flu vaccine by the end of October. However, getting vaccinated early (for example, in July or August) is likely to be associated with reduced protection against flu infection later in the flu season, particularly among older adults. Children who need two doses of vaccine to be protected should start the vaccination process sooner because the two doses must be given at least four weeks apart. 

People who should not get the flu shot

This includes children younger than 6 months of age are too young to get a flu shot, and people with severe, life-threatening allergies to the flu vaccine or any ingredient in the vaccine. You can check the details here. 

Where to get a flu shot amid Covid-19 pandemic?

A person can safely get a flu vaccine at multiple locations such as the doctor’s office, health departments, and pharmacies. You can check the VaccineFinder.org to find where flu vaccines are available near you. You can also check CDC interim guidance for immunization services during the coronavirus pandemic, meant at helping immunization providers in multiple clinical and alternative settings with the safe administration of vaccines.