M-A | Past SARS-CoV-2 infection provides long-lasting protection against severe disease caused by all variants

Summary: The article describes a systematic review and meta-analysis of studies assessing protection from past SARS-CoV-2 infection against subsequent re-infection, symptomatic COVID-19 disease, and severe disease. The researchers identified 65 studies from 19 different countries and found that protection from past infection against re-infection from pre-omicron variants was high and remained so even after 40 weeks. However, protection was substantially lower for the omicron BA.1 variant and declined more rapidly over time than protection against previous variants. Protection from severe disease was high for all variants, estimated at 90·2% for ancestral, alpha, and delta variants, and 88·9% for omicron BA.1 at 40 weeks. The study highlights the importance of considering past infection in assessing future disease burden from COVID-19, providing guidance on when individuals should be vaccinated, and designing policies that mandate vaccination for workers or restrict access. The findings also suggest that individuals with a documented infection should be treated similarly to those who have been fully vaccinated with high-quality vaccines.

Article: Past SARS-CoV-2 infection protection against re-infection: a systematic review and meta-analysis – The Lancet

News Release: The Lancet: Most comprehensive study to date provides evidence on natural immunity protection by COVID-19 variant and how protection fades over time – Institute for Health Metrics and Evaluation

Commentaries:

Previous COVID-19 may slash severe illness at reinfection by 89% – CIDRAP

Natural Immunity Against COVID-19 ‘At Least’ On Par With Vaccination in Preventing Death – Health Policy Watch