Human Vaccines & Immunotherapeutics: News July 2022.

Abstract

The US Food and Drug Administration (FDA) has granted emergency-use authorization to the adjuvanted protein subunit vaccine NVX-CoV2373 (Novavax) for use in adults. The decision is based on a Phase 3 clinical trial showing >90% overall efficacy against Covid-19 infection with 80% efficacy in older adults. Many countries have started vaccinating their populations with the fourth dose of an mRNA vaccine. A study of >40,000 elderly residents of long-term care facilities in Israel showed that the fourth dose of the BNT162b2 vaccine (Pfizer & BioNTech) decreases the risk of hospitalization and death due to infection with the Omicron variant by 64% and 72%, respectively, compared to the three-dose regimen alone. Vaccines are also being developed specific for emerging variants of SARS-CoV-2. The Omicron-specific booster vaccine mRNA-1273.214 (Moderna) elicited 1.7-fold higher levels of neutralizing antibodies, compared to the parental booster vaccine mRNA-1273. These antibodies were specific for strains BA.4 and BA.5 currently in circulation. Mucosal immunity was stimulated by the oral tablet vaccine VXA-CoV2–1 (Vaxart) in a Phase 1 trial involving 35 healthy adults. The vaccine, which comprises a non-replicating adenoviral vector expressing the spike and nucleocapsid antigens with a double-stranded RNA adjuvant, elicited IgA antibodies reactive against multiple coronaviruses and persistent for at least one year.