By Nidhi Saha, BDSJul 25 2022Reviewed by Aimee Molineux A new study posted to the medRxiv* preprint server reported the outcomes of a clinical trial evaluating an oral vaccine candidate against severe acute respiratory syndrome coronavirus 2 .
The development of mucosal vaccines for various microbial diseases, such as SARS-CoV-2, is a major field of research. This is because SARS-CoV-2 infection begins in the upper respiratory tract and largely affects the respiratory mucosa. Consequently, if a mucosal vaccination against SARS-CoV-2 is developed, it would offer the required level of protection at the infection site, thereby preventing infections and inhibiting virus replication in the upper respiratory tract.
The study A phase 1 clinical trial was conducted in a single center, open-label, dose-ranging fashion to determine the tolerance and efficacy of two dose levels of the oral COVID-19 vaccine candidates, designated as VXA-CoV2-1. Safety was the primary goal of this trial. The immunogenicity secondary endpoint was evaluated during the active phase largely by quantifying IgA and IgG in the nose, serum, and saliva samples. The long-term durability of available volunteers was evaluated.
Convalescents and VXA-CoV2-1 produced comparable amounts of IgA in the nose and saliva. Additionally, researchers noted that vaccine-immunized patients have enhanced mucosal neutralizing antibody responses, implying that vaccination may enhance the quality of antibody responses on mucosal surfaces. Mucosal IgA produced by VXA-CoV2-1 was cross-reactive to the Omicron and the Delta variants of SARS-CoV-2.