What is a Flu Shot?

What is a Flu Shot?

The flu shot, or influenza vaccine, is a vaccine that helps protect against the flu. Although flu vaccines are not 100% effective against all seasonal influenza strains, the best way to prevent the flu is to get the vaccine once a year.

The flu shot vaccine helps protect against the most common seasonal strains and is administered via a quick jab in the arm or nasal spray.

When to get a Flu Shot?

When to get a Flu Shot?

In the United States, flu season occurs in the fall and winter. While the timing of the upcoming flu season can fluctuate around the country and differ yearly, the most effective flu shot months are September and October.

It takes about two weeks for the flu vaccine to start providing protection. The seasonal flu shot is typically available from September to spring. The earlier you get it, ideally before the end of October, the better.

Protection from the influenza vaccine can last for about six months, so one shot per year will get you through the flu season. A flu booster, or second shot, is generally only beneficial to children ages 6 months to eight years, especially if they are being vaccinated for the first time.

Who Should Get a Flu Shot?

Who Should Get a Flu Shot?

The CDC recommends that everyone six months and older get an annual flu shot, with rare exceptions. Flu vaccines are strongly encouraged for healthcare workers and individuals at higher risk of developing serious flu complications.

Groups at are higher risk of developing serious flu complications:

Where Can I Get a Flu Shot?

Who Should Get a Flu Shot?

You can get a flu shot from a primary care doctor, a hospital, a walk-in health clinic, mobile vaccine units, pharmacy, schools, workplaces, a local health department or family center.

NewYork-Presbyterian offers seasonal flu vaccines at many of our hospital, medical group, and ambulatory care locations.

Benefits of Flu Vaccines


Scientists create a new influenza vaccine every year to combat the ever-evolving influenza strains caused by the flu virus. A flu shot can protect you from three or four seasonal flu strains.

A flu vaccine can help:

  • Prevent illness
  • Reduce your risk of hospitalization from the flu
  • Lessen the severity of your flu symptoms

Side Effects of the Flu Vaccine

Side Effects

Generally, any side effects from the flu shot will be mild compared to influenza symptoms. The risk of an allergic reaction, harm, or death from the flu vaccine is rare.

Common side effects from the flu shot usually only last for a day or two, and can include:

  • Redness, soreness, and swelling at the site of the injection
  • Muscle aches
  • Headache
  • Fever
  • Nausea
  • Fatigue

The influenza vaccine can be given as a nasal spray to people ages 2 to 49. Side effects from the nasal spray can include:

  • Headache
  • Cough
  • Nasal congestion/runny nose
  • Sore throat
  • Fever
  • Muscle aches



It takes about two weeks for the body to develop protective antibodies after receiving the flu vaccine.

Drink plenty of water after receiving the flu shot to avoid dehydration.

Adults can receive the pneumococcal and flu vaccinations at the same doctor’s visit.

Individuals contract the influenza virus from other people—droplets from coughing, sneezing, or talking can travel from the infected person to your mouth and nose or be inhaled into the lungs.

In general, flu vaccines are around 40% to 60% effective against seasonal strains.

No, you cannot get the flu from the flu shot. The flu vaccine is made from an inactivated virus that cannot transmit infection.

For the 2022-2023 season, the flu vaccines are quadrivalent vaccines made to combat four different flu strains.

The effectiveness of flu vaccine can last for six months.

Flu shot ingredients generally include deactivated influenza viruses and stabilizers.
Get Care

Get a Flu Vaccine at NewYork-Presbyterian

NewYork-Presbyterian offer expert primary care services, including the annual flu shot. We provide off-peak and weekend hours for easy scheduling, a user-friendly patient portal, and access to world-class NewYork-Presbyterian specialists. We accept most insurances.

Contact NewYork-Presbyterian or one of our medical group locations and get your flu shot today.