Transmission & Prevention
· How effective have the vaccines been? A team from the United States Centers for Disease Control COVID-19 Response Team evaluated the effectiveness of messenger RNA (mRNA) COVID-19 vaccines against SARS-CoV-2 infection in a cohort of 3,950 health care personnel and other essential workers who underwent weekly SARS-CoV-2 testing for 13 consecutive weeks. They found vaccine effectiveness for prevention of infection was 90% for full immunization (0.04 infections per 1,000 person-days; ≥14 days after second dose) and 80% for partial immunization (0.19 infections per 1,000 person-days; ≥14 days after first dose and before second dose). The authors suggest mRNA vaccines effectively prevent SARS-CoV-2 infection and emphasize the importance of COVID-19 vaccination in all eligible individuals.