You wake up suddenly with a fever, chills, cough, and body aches. “Flu” immediately crosses your mind, but you already got your vaccine this year. Although you think that getting the flu shot protects you from harm’s way, you may be in the wrong. This year’s flu virus has been more aggressive than in past years, and it has only just begun.

Flu season typically starts at the beginning of October and ends in May. However, this year’s influenza surveillance season began on Sept. 29, 2019, and will run through May 16, 2020. Flu activity is increasing as a whole all around the country. In less than three months, there have already been 4,424 cases of influenza in Pennsylvania. Bucks county alone has had 112 cases. Citizens all around the country are at risk of catching the flu because this year’s vaccine is not as successful as the World Health Organization had hoped.

The strains that the vaccine is designed to target do not match the strains circulating the country, influenza A and influenza B. However, even if the strains predicted are correct, they can mutate, rendering the vaccine ineffective against that strain. The rate of influenza-like illness has been over the national baseline of 2.4% for a month now. Nine out of the ten United States regions have reported elevated flu activity.

Typically, influenza B activity occurs near the end of the flu season. This year happens to be an exception: of the positive flu tests, 75.4% of them were influenza B, even though we are still in the early stages of flu season. “It’s unusual for there to be this much influenza B activity at this time of year,” said Kristen Nordlund, a spokesperson for the CDC. This strain has been fluctuating greatly. Last year the activity for influenza B was unusually low.

“Even if the vaccine is not a perfect match, it  may still provide some protection from getting severely ill,” says Dr. Weiss, an emergency medicine physician at Stanford Health Care. Although the flu shot may not protect you from contracting the flu, it can help to decrease the severity of your symptoms at the very least.