COVID-NET is a population-based surveillance system that collects reports of lab-confirmed COVID-19-related hospitalizations in 99 counties in 14 states. This system provides the most complete data on vaccine breakthrough in the general population. One important system that CDC uses to track vaccine breakthrough infections is COVID-NET ( the Coronavirus Disease 2019 -Associated Hospitalization Surveillance Network). CDC also collects data on vaccine breakthrough infections through outbreak investigations. How CDC Monitors Breakthrough InfectionsĬDC has multiple surveillance systems and ongoing research studies to monitor the performance of vaccines in preventing infection, disease, hospitalization, and death. Therefore, everyone aged 12 years and older should get vaccinated to protect themselves and those around them, including family members who are not able to be vaccinated from severe disease and death. However, the risk of infection, hospitalization, and death are all much lower in vaccinated compared to unvaccinated people. Overall, if there are more infections with SARS-CoV-2 (the virus that causes COVID-19) there will be more vaccine breakthrough infections. However, studies so far indicate that the vaccines used in the United States work well against the Delta variant, particularly in preventing severe disease and hospitalization. The Delta variant is more contagious than previous variants of the virus that causes COVID-19. However, some people who are fully vaccinated will get COVID-19. Research shows that the FDA-authorized vaccines offer protection against severe disease, hospitalization, and death against currently circulating variants in the United States. Vaccine Breakthroughs and VariantsĬDC continues to actively monitor vaccine safety and effectiveness against new and emerging variants for all FDA-authorized COVID-19 vaccines. Vaccines remain effective in protecting most people from COVID-19 infection and its complications. Studies so far show that vaccinated people are 8 times less likely to be infected and 25 times less likely to experience hospitalization or death. However, the risk of infection remains much higher for unvaccinated than vaccinated people. Because vaccines are not 100% effective, as the number of people who are fully vaccinated goes up, the number of vaccine breakthrough infections will also increase.
However, since vaccines are not 100% effective at preventing infection, some people who are fully vaccinated will still get COVID-19. Most people who get COVID-19 are unvaccinated. Further, CDC recommends that moderately to severely immunocompromised people receive an additional dose of vaccine.ĬOVID-19 vaccines are effective at preventing infection, serious illness, and death. They should continue to take all precautions recommended for unvaccinated people, until advised otherwise by their healthcare professional.