What Is COVID-19?

About COVID-19

The Janssen COVID‑19 Vaccine has not been approved or licensed by the U.S. Food and Drug Administration (FDA), but has been authorized by FDA through an Emergency Use Authorization (EUA) for active immunization to prevent Coronavirus Disease 2019 (COVID‑19) in individuals 18 years of age and older.

What Is COVID-19?

COVID‑19 is caused by a coronavirus called SARS-CoV-2. This type of coronavirus has not been seen before. You can get COVID‑19 through contact with another person who has the virus. It is predominantly a respiratory illness that can affect other organs. People with COVID‑19 have had a wide range of symptoms reported, ranging from mild symptoms to severe illness. Symptoms may appear 2 to 14 days after exposure to the virus.

Common symptoms may include:
  • Fever or chills
  • Cough
  • Shortness of breath
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

How Do COVID‑19 Vaccines Work?

According to the Centers for Disease Control and Prevention at CDC.gov:

COVID-19 vaccines help our bodies develop immunity to the virus that causes COVID-19 without us having to get the illness. Different types of vaccines work in different ways to offer protection, but with all types of vaccines, the body is left with a supply of “memory” T-lymphocytes as well as B-lymphocytes that will remember how to fight that virus in the future.

It typically takes a few weeks for the body to produce T-lymphocytes and B-lymphocytes after vaccination.

Sometimes after vaccination, the process of building immunity can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity.

MORE INFORMATION ABOUT COVID‑19 VACCINES AND HOW THEY WORK
Learn more about how vaccine works

COVID-19=coronavirus disease 2019; SARS-CoV-2=severe acute respiratory syndrome coronavirus 2.

Important safety information

Important safety information