Why are vaccinated people still getting COVID-19?

Michigan health officials reported that 246 fully vaccinated people had tested positive for COVID-19 through March.

Read More: Of 1.7M fully vaccinated in Michigan, 246 have tested positive for COVID-19

The state did note that some of those positive cases could have been people who were positive before they got vaccinated.

All of the 246 people were fully vaccinated. "Fully vaccinated" means that the person received the second dose of the Pfizer or Moderna and it has been 14 days since then.

According to state health officials, of the positive cases, 129 had no data entered about hospitalizations, while 117 did have that information. Eleven were hospitalized, 103 were not, and three were marked as unknown.

Additionally, three people older than 65 have died. Two of those deaths were within three weeks of completion of vaccination.

According to the Michigan Department of Health and Human Services, more than 1.7 million people have received both vaccine doses. This means that .0001 of those vaccinated have gotten sick.

The Pfizer vaccine is considered 95% effective and the Moderna vaccine is considered 94% effective, so they are not 100% guaranteed to prevent infection. However, the vaccine has been shown to reduce how sick a person gets if they contract the illness after the shots. Health officials said that people who get sick after being vaccinated tend to experience less severe symptoms.

Related: What's leading Michigan's COVID-19 case rates to highest in the nation?

The Centers for Disease Control and Prevention have advised that people who are vaccinated should continue to wear masks and follow social distancing protocols until more about how the vaccine impacts the spread of the virus is understood.

Officials said the majority of the population develops full immunity within 14 days of completion of their vaccine series, but a small proportion appears to take longer to get a full antibody response.

The health department reiterated that the proportion of vaccinated people who have been symptomatic, hospitalized, or have died are lower than those who are unvaccinated.