Herd Immunity against Severe Acute Respiratory Syndrome Coronavirus 2 Infection in 10 Communities, Qatar
Andrew Jeremijenko, Hiam Chemaitelly, Houssein H. Ayoub, Moza Alishaq, Abdul‐Badi Abou‐Samra, Jameela Ali Al Ajmi, Nasser Ansari, Zaina Al Kanaani, Abdullatif Al Khal, Einas Al‐Kuwari, Ahmed Al‐Mohammed, Naema Hassan Abdulla Al Molawi, Huda Mohamad Al Naomi, Adeel A. Butt, Peter Coyle, Reham Awni El Kahlout, Imtiaz Gillani, Anvar Hassan Kaleeckal, Naseer Ahmad Masoodi, Anil George Thomas, Hanaa Nafady‐Hego, Ali Nizar Latif, Riyazuddin Mohammad Shaik, Nourah Younes, Hanan F. Abdul Rahim, Hadi M. Yassine, Mohamed Ghaith Al‐Kuwari, Hamad Eid Al‐Romaihi, Mohamed H. Al‐Thani, Roberto Bertollini, Laith J. Abu‐Raddad
Abstract
We investigated what proportion of the population acquired severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and whether the herd immunity threshold has been reached in 10 communities in Qatar. The study included 4,970 participants during June 21-September 9, 2020. Antibodies against SARS-CoV-2 were detected by using an electrochemiluminescence immunoassay. Seropositivity ranged from 54.9% (95% CI 50.2%-59.4%) to 83.8% (95% CI 79.1%-87.7%) across communities and showed a pooled mean of 66.1% (95% CI 61.5%-70.6%). A range of other epidemiologic measures indicated that active infection is rare, with limited if any sustainable infection transmission for clusters to occur. Only 5 infections were ever severe and 1 was critical in these young communities; infection severity rate of 0.2% (95% CI 0.1%-0.4%). Specific communities in Qatar have or nearly reached herd immunity for SARS-CoV-2 infection: 65%-70% of the population has been infected.