Researchers at the University of Virginia Highlight the Need for Enhanced Immune Response
Virginia, USA – Researchers at the University of Virginia (UVA) have emphasized the critical role of intranasal vaccines in protecting individuals against emerging variants of concern of the SARS-CoV-2 virus. The study, published in the journal Science Immunology, reveals that current COVID-19 vaccinations, while effective in preventing serious illness, may not be sufficient to curb the spread of the virus and its variants.
Underperforming Immune Response in Vaccinated Individuals
The UVA researchers observed that individuals who received COVID-19 vaccinations exhibited an underperforming immune response in the airways compared to those who had natural infection. This finding prompted the researchers to suggest that an intranasal vaccine-boosting strategy is essential to protect people from emerging variants of concern.
The Difference in Vaccine Mechanisms
Unlike the mRNA vaccines currently available, which focus on stimulating the immune response in the blood, intranasal vaccines deliver the vaccine directly to the mucosal linings of the respiratory tract. The study reveals that mucosal linings experienced only moderate or minimal neutralizing antibody response with current vaccines.
Nasally Delivered Vaccine Demonstrates Promising Results
The researchers found that mice administered a nasally delivered vaccine, based on an adenovirus expressing the spike protein found in COVID-19, showed robust neutralizing antibody responses when combined with mRNA vaccine shots. This combination enhanced both cellular and humoral immunity and proved effective against both the ancestral virus and the Omicron variant.
Importance of Mucosal Immunity
The study also supports the notion that developing immunity at the site where the virus initially takes root, the mucus membranes of the nose, can lead to greater protection against the coronavirus. Strong antibody responses in the respiratory tract can neutralize the virus upon entry, preventing viral infection and transmission.
Future Prospects of Nasal Vaccines
While pharmaceutical labs are working on nasal vaccines for COVID-19, none have been approved for use yet. Developing a nasal spray vaccine requires careful balance, as a weakened version of the live virus is needed for effectiveness. Safety concerns, including the potential for side effects like Bell’s palsy, have delayed the approval of adenovirus-based nasal vaccines.