Understanding COVID-19 vaccine efficacy

• Published in: Science (American Association for the Advancement of Science) Vol. 370; no. 6518; pp. 763 - 765
• Main Authors: Lipsitch, Marc, Dean, Natalie E.
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 13.11.2020
• Subjects: Age Factors; Betacoronavirus - immunology; Betacoronavirus - physiology; Clinical Laboratory Techniques; Clinical Trials, Phase III as Topic; Coronavirus Infections - diagnosis; Coronavirus Infections - immunology; Coronavirus Infections - prevention & control; Coronavirus Infections - transmission; Coronavirus Infections - virology; Coronaviruses; COVID-19; COVID-19 Testing; COVID-19 Vaccines; Disease control; Disease transmission; Humans; Immune response; Influenza; Observational Studies as Topic; Older people; Pandemics - prevention & control; Pneumonia, Viral - immunology; Pneumonia, Viral - prevention & control; Pneumonia, Viral - transmission; Pneumonia, Viral - virology; Randomized Controlled Trials as Topic; Risk; Risk groups; SARS-CoV-2; Vaccination; Vaccine efficacy; Vaccines; Viral diseases; Viral Load; Viral Vaccines - administration & dosage; Viral Vaccines - adverse effects; Viral Vaccines - immunology; Virus Shedding; Young adults
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.abe5938

Vaccine efficacy in high-risk groups and reduced viral shedding are important for protection The elderly and people with comorbidities are at greatest risk of severe coronavirus disease 2019 (COVID-19). A safe and effective vaccine could help to protect these groups in two distinct ways: direct protection, where high-risk groups are vaccinated to prevent disease, and indirect protection, where those in contact with high-risk individuals are vaccinated to reduce transmission. Influenza vaccine campaigns initially targeted the elderly, in an effort at direct protection, but more recently have focused on the general population, in part to enhance indirect protection. Because influenza vaccines induce weaker, shorter-lived immune responses in the elderly than in young adults, increasing indirect protection may be a more effective strategy. It is unknown whether the same is true for COVID-19 vaccines.