Cavalcante T, Barboza W, Martins-Filho PR. The vaccination status of COVID-19 hospitalized patients during the Omicron BQ.1.1 wave in Northeast Brazil suggests the need for a fifth booster dose in the elderly, with a time since the last dose of more than 6 months . EXCLI J. [Internet]. 2023 Feb. 1 [cited 2024 Apr. 25];22:169-72. Available from: https://www.excli.de/index.php/excli/article/view/5807