Post Covid-19 antibodies reduce the chance of reinfection for almost a year after initial infection

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  • A study focused on home care workers and residents as they are a high-risk group for Covid-19
  • The results showed a reduced chance of reinfection for up to 10 months after their first infection
  • Residents had higher immunity than healthcare workers

A new study has found that the risk of people being reinfected with SARS-CoV-2, which causes Covid-19, is substantially reduced for up to 10 months after their first infection.

The research published in Lancet Healthy Longevity investigated the association between SARS-CoV-2 antibody status at the start of the study and subsequent infection in staff and residents of long-term care facilities.

A high-risk population

The study focused on home care workers and residents as they are seen as a high-risk group for Covid-19 infection.

The researchers collected blood samples of more than 2 000 care facility residents and staff from 100 homes. The staff were all under the age of 65. Blood samples were collected and tested for antibodies to SARS-CoV-2 at three different stages: at the start, and then after the second and fourth months. 

The researchers compared people who had previous infections with those who were not infected with the virus. Covid-19 testing was conducted weekly in the case of staff, and monthly for residents. 

Antibodies provide effective protection 

The study results show that the risk of the previously infected participants becoming reinfected with Covid-19 was significantly lower for up to 10 months following the first infection.

The researchers found that residents with a previous infection were 85% less likely to be reinfected during a period of four months than residents who had never been infected – while staff with past infection were 60% less prone to reinfection than staff with no previous infection.

The research, however, shows that a very small number of staff and residents were reinfected. Of the 34 people who had been previously infected, reinfections occurred in only four residents and 10 members of staff – while out of the 1 477 participants who had never been infected, 93 residents and 111 staff tested positive for the virus.

“The risk of SARS-CoV-2 reinfection was substantially reduced in staff and residents of long-term care facilities who were SARS-CoV-2 antibody-positive, and the observed reinfections were not clinically severe.

"Understanding the correlates of immunity that protect against future infection will be fundamental to policy decisions regarding long-term care facilities, including re-vaccination schedules and the ongoing need for non-pharmaceutical interventions to prevent SARS-CoV-2 transmission,” the authors wrote.

*For more Covid-19 research, science and news, click here

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