Most fully vaccinated residents of nursing homes were not infected, even after someone in the same facility tested positive for Covid-19, according to a new study that looked at infections in nursing homes in Chicago from the US Centers for Disease Control and Prevention.
Among the nearly 8,000 residents and nearly 7,000 staff that have received two doses of a Covid-19 vaccine since December, there were only 22 breakthrough infections among the fully vaccinated, according to the CDC’s Weekly Morbidity and Mortality Report published on Wednesday.
The CDC considers people to be fully vaccinated two weeks after the second dose of the Pfizer or Moderna vaccine or two weeks after the single Johnson & Johnson vaccine.
Of the 22 breakthrough cases, there were 12 residents and 10 staff members who tested positive for Covid-19 after being fully vaccinated. Two-thirds of those who tested positive, 14 people, were asymptomatic. Two residents were hospitalized and one of those residents died, the CDC said. The person who died had three underlying conditions, according to the CDC.
There was no facility-associated secondary transmission.
Although they are rare, the CDC said breakthrough infections can happen because no Covid-19 vaccine provides 100% protection. While some earlier studies suggested that the vaccines provide total protection against severe illness and death, data on vaccination and transmission in congregate settings like nursing homes has been limited.
Some context: The CDC said that this study confirms how important it is for people to get vaccinated, particularly in congregate settings where it is difficult to keep physical distance.
The study also shows that nursing homes still need to follow recommended infection and control practices. Residents who get Covid-19 still need to be isolated from others and residents that have had close contact with them should be quarantined. Nursing homes should continue regular testing and staff should continue to wear PPE, regardless of vaccination status.
“Maintaining high vaccination coverage among residents and staff members is also important to reduce opportunities for transmission within facilities and exposure among persons who might not have achieved protective immunity after vaccination,” the report concluded.