“The failure of the current generation of SARS-CoV-2 vaccines delivered by the intramuscular (IM) route to block infection likely relates to their inability to induce robust mucosal immune responses at the portal of entry,” said corresponding author Dan H. Barouch, MD, PhD, director of the Center for Vaccine and Virology Research at BIDMC.
“In this study, we demonstrated that novel immunization strategies can markedly increase mucosal immunity in nonhuman primates and improve protective efficacy against a mucosal virus challenge.”
Barouch and colleagues primed 40 adult rhesus macaques with the Ad26 COVID-19 vaccine (Janssen/Johnson & Johnson) administered intramuscularly (IM)–like a shot in the arm adults typically receive.
Approximately a year later, the animals received a booster. Three groups received either a dose of the Ad26 vaccine via the IM route, the intranasal (IN) route (delivered via nasal spray), or the intratracheal (IT) route (delivered by nebulizer or inhaler). A fourth group received a dose of the bivalent mRNA vaccine (Pfizer-BioNTech) by the IN route. A sham group received no boosters.
When the macaques were later challenged with a high dose of the virus, the investigators sampled the animals’ blood, nasal and lung fluids to monitor their immune responses. They found that the ,b>Ad26 booster administered via the IT route provided near complete protection against a high-dose SARS-CoV-2
Advertisement
In contrast, mRNA IN boosting proved ineffective, suggesting that improved formulations will likely be required for effective mucosal delivery of mRNA vaccines.
Reference :
- Mucosal boosting enhances vaccine protection against SARS-CoV-2 in macaques – (https://www.nature.com/articles/s41586-023-06951-3)
Source: Eurekalert
