Globally, about 150 million people have had the virus that causes COVID-19, and over 3 million have died from it (https://www.worldometers.info/coronavirus/). Many people who have had the infection are worried about the risk of catching COVID-19 again (reinfection). Until now, there have been eight major studies estimating protection against reinfection with participants from Austria, Denmark, Qatar, Switzerland, the United Kingdom, and the U.S. The research suggests a range of protection between 80 – 95%.
Risk of reinfection is very low
A new study from the Middle East looked at reinfection rate in more detail. Researchers monitored 43,044 antibody-positive people for 35 weeks. They used a process called viral genome sequencing to better understand how the virus spreads and how well certain interventions work. This study confirmed that reinfection does occur, but only rarely. For example, around 2 in every 1,000 persons will be reinfected. For antibody-negative people, the risk of infection was much higher. This means that after one infection, a person will be protected against another infection for 95% of the time over the next 7 months. The study also showed no evidence for this protection wearing off over time within 7 months.
Antibody-negative people need vaccination
These findings suggest that immunity, whether through natural infection or vaccination, works very well to prevent infection (>90%) and may last for at least 7 months. The results also suggest that, if vaccine is in short supply, vaccinating people who are antibody-negative should be prioritized.