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Vaccinated individuals who become infected can transmit the virus to others.
However, several factors—including viral variant, timing of infection, and immune response—affect how contagious someone may be.
Because transmission remains possible, people experiencing symptoms consistent with COVID-19 should consider testing and follow local public health guidance regarding isolation and precautions.
Who Remains at Higher Risk?
Some groups continue to face increased risk of severe illness even after vaccination.
These include:
Older adults
Individuals with chronic heart disease
People with chronic lung disease
Those with diabetes
Cancer patients
Organ transplant recipients
Individuals receiving immunosuppressive medications
These populations may benefit from additional preventive measures recommended by healthcare professionals.
Long COVID
One ongoing area of research involves Long COVID, also called post-COVID condition.
Some individuals experience symptoms lasting weeks or months after the initial infection.
Possible symptoms include:
Fatigue
Brain fog
Shortness of breath
Sleep disturbances
Loss of concentration
Persistent cough
Changes in taste or smell
Research suggests vaccination may reduce—but does not eliminate—the risk of developing Long COVID.
Scientists continue studying why some individuals experience prolonged symptoms while others recover quickly.
Everyday Prevention Still Matters
Vaccination is one layer of protection rather than the only preventive strategy.
Depending on personal risk and local circumstances, additional precautions may include:
Staying home when ill
Washing hands regularly
Improving indoor ventilation
Wearing a well-fitting mask in high-risk settings if recommended
Covering coughs and sneezes
Testing when symptoms develop
Protecting vulnerable family members
These measures help reduce transmission of many respiratory illnesses, not only COVID-19.
Common Misunderstandings
Myth: If vaccinated people get COVID-19, vaccines don’t work.
This is incorrect.
Vaccines are designed primarily to reduce serious illness, hospitalization, and death. While they can also reduce infection risk, especially shortly after vaccination, preventing every infection is not realistic for rapidly evolving respiratory viruses.
Myth: Natural infection is always better than vaccination.
Infection does produce immune responses, but it also carries risks of severe disease, hospitalization, Long COVID, and complications. Vaccination provides immune training without requiring a person to experience the full risks associated with infection.
Myth: Healthy people don’t need protection.
Although younger, healthier individuals often recover well, serious illness can still occur. In addition, infected individuals may transmit the virus to more vulnerable members of their community.
What Should You Do If You Become Sick?
If you develop symptoms that could be COVID-19: