The Centers for Disease Control and Prevention (CDC) has formally recommended the Novavax COVID-19 vaccine for adolescents ages 12 through 17. But there are things the public should know about the vaccine before getting jabbed.

In its recommendation published Monday, the CDC said the Novavax vaccine contains “harmless proteins of the COVID-19 virus” alongside an adjuvant that helps the immune system respond to a SARS-CoV-2 infection.

The public health agency said the protein subunit technology used by Novavax has been around for more than three decades in the U.S. It was first used in the hepatitis B vaccine. At present, the same technology is used in influenza and whooping cough vaccines.

“Novavax’s COVID-19 vaccine, which is available now, is an important tool in the pandemic and provides a more familiar type of COVID-19 vaccine technology for adolescents. Having multiple types of vaccines offers more options and flexibility for the public, jurisdictions, and vaccine providers,” the CDC wrote.

However, the U.S. Food and Drug Administration (FDA) warned of the Novavax vaccine’s side effects when it authorized its use for emergency cases in the country.

The FDA indicated in a late July press release that Novavax reportedly causes a slew of side effects, including pain or tenderness, redness and swelling at the site of injection. Vaccine recipients also experienced fatigue, muscle pain, headache, joint pain, fever, nausea and vomiting.

Per a more in-depth report by the FDA, Novavax showed the following side effects in clinical trials: myocarditis (inflammation of the heart), pericarditis (inflammation of the lining outside the heart), decreased appetite, chills, hives, swelling of the face and swollen lymph nodes.

According to the FDA, the Novavax vaccine can prevent COVID-19, but the duration of protection it provides is still unknown. The vaccine is authorized for emergency use in kids 12 years of age and older as a two-dose primary series. The doses are to be administered three weeks apart.

Other vaccine brands also have their long list of possible side effects. But experts said people should be more worried about catching SARS-CoV-2 without prior immune protection. The benefits outweigh the risks, and the vaccines are known to prevent severe illness, hospitalization and death.