Effectiveness of Homologous and Heterologous COVID-19 Booster Doses Following 1 Ad.26.COV2.S (Janssen [Johnson &amp; Johnson]) Vaccine Dose Against COVID-19–Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults — VISION Network, 10 States, December 2021–March 2022
Authors: Karthik Natarajan, Namrata Prasad, Kristin Dascomb, Stephanie A. Irving, Duck-Hye Yang, Manjusha Gaglani, Nicola P. Klein, Malini B. DeSilva, Toan C. Ong, Shaun J. Grannis, Edward Stenehjem, Ruth Link-Gelles, Elizabeth A. Rowley, Allison L. Naleway, Jungmi Han, Chandni Raiyani, Gabriela Vazquez Benitez, Suchitra Rao, Ned Lewis, William F. Fadel, Nancy Grisel, Eric P. Griggs, Margaret M. Dunne, Melissa S. Stockwell, Mufaddal Mamawala, Charlene McEvoy, Michelle A. Barron, Kristin Goddard, Nimish R. Valvi, Julie Arndorfer, Palak Patel, Patrick K Mitchell, Michael Smith, Anupam B. Kharbanda, Bruce Fireman, Peter J. Embi, Monica Dickerson, Jonathan M. Davis, Ousseny Zerbo, Alexandra F. Dalton, Mehiret H. Wondimu, Eduardo Azziz-Baumgartner, Catherine H. Bozio, Sue Reynolds, Jill Ferdinands, Jeremiah Williams, Stephanie J. Schrag, Jennifer R. Verani, Sarah Ball, Mark G. Thompson, Brian E. Dixon
Journal: MMWR Morbidity and Mortality Weekly Report (2022)

CDC recommends that all persons aged ≥18 years receive a single COVID-19 vaccine booster dose ≥2 months after receipt of an Ad.26.COV2.S (Janssen [Johnson & Johnson]) adenovirus vector-based primary series vaccine; a heterologous COVID-19 mRNA vaccine is preferred over a homologous (matching) Janssen vaccine for booster vaccination. This recommendation was made in light of the risks for rare but serious adverse events following receipt of a Janssen vaccine, including thrombosis with thrombocytopenia syndrome and Guillain-Barré syndrome† (1), and clinical trial data indicating similar or higher neutralizing antibody response following heterologous boosting compared with homologous boosting (2). Data on real-world vaccine effectiveness (VE) of different booster strategies following a primary Janssen vaccine dose are limited, particularly during the period of Omicron variant predominance. The VISION Network§ determined real-world VE of 1 Janssen vaccine dose and 2 alternative booster dose strategies: 1) a homologous booster (i.e., 2 Janssen doses) and 2) a heterologous mRNA booster (i.e., 1 Janssen dose/1 mRNA dose). In addition, VE of these booster strategies was compared with VE of a homologous booster following mRNA primary series vaccination (i.e., 3 mRNA doses). The study examined 80,287 emergency department/urgent care (ED/UC) visits¶ and 25,244 hospitalizations across 10 states during December 16, 2021-March 7, 2022, when Omicron was the predominant circulating variant.** VE against laboratory-confirmed COVID-19-associated ED/UC encounters was 24% after 1 Janssen dose, 54% after 2 Janssen doses, 79% after 1 Janssen/1 mRNA dose, and 83% after 3 mRNA doses. VE for the same vaccination strategies against laboratory-confirmed COVID-19-associated hospitalizations were 31%, 67%, 78%, and 90%, respectively. All booster strategies provided higher protection than a single Janssen dose against ED/UC visits and hospitalizations during Omicron variant predominance. Vaccination with 1 Janssen/1 mRNA dose provided higher protection than did 2 Janssen doses against COVID-19-associated ED/UC visits and was comparable to protection provided by 3 mRNA doses during the first 120 days after a booster dose. However, 3 mRNA doses provided higher protection against COVID-19-associated hospitalizations than did other booster strategies during the same time interval since booster dose. All adults who have received mRNA vaccines for their COVID-19 primary series vaccination should receive an mRNA booster dose when eligible. Adults who received a primary Janssen vaccine dose should preferentially receive a heterologous mRNA vaccine booster dose ≥2 months later, or a homologous Janssen vaccine booster dose if mRNA vaccine is contraindicated or unavailable. Further investigation of the durability of protection afforded by different booster strategies is warranted.