Yes. The vaccines are very effective against symptomatic COVID-19 illness. Vaccine efficacy is determined by comparing the number of symptomatic cases in vaccinated people to the number of symptomatic cases in unvaccinated people.
The vaccine efficacy trials were performed in different populations at different times, so it is impossible to directly compare the available vaccines. For the prevention of symptomatic COVID-19, Pfizer vaccine efficacy rate is reported as 95%, Moderna vaccine efficacy rate is 94.1%, and Johnson & Johnson vaccine efficacy rate is 66% (although 72% in the United States). These are all very good efficacy rates for vaccines. In contrast, influenza vaccines are about 40-60% effective.
All COVID-19 vaccines were highly effective (over 89%) against COVID-19 severe enough to require hospitalization. In the vaccine trials, no participants who received a COVID-19 vaccine died from COVID-19.
In these trials, efficacy of the vaccine was similar across demographic groups, including those with different ages, races and ethnicities, and underlying health conditions.
The CDC has been continuously monitoring the safety and efficacy of COVID-19 vaccines. During Omicron, the CDC has identified that COVID-19 associated hospitalization rates increased for all adults, regardless of vaccination status. However, rates were 12 times higher among adults who were unvaccinated compared to adults who received booster or additional doses.
There is also evidence that the mRNA vaccines continued to be highly effective at protecting against COVID-19 associated invasive ventilation (the need for a breathing tube) or death. CDC has identified that the protection was highest in adults who received the third dose, reducing the risk of COVID-19 associated ventilation or death during the Omicron period by 94%.
For more information, see CDC Newsroom: COVID-19 vaccines continue to protect against hospitalization and death among adults.