On Jun. 22, 2020, Intravacc announced promising results of a preclinical study with its experimental whooping cough vaccine in mice. Published in Scientific Reports (2020) 10:7396, the study showed that intranasal immunization induced both excellent systemic and local immune responses, but also prevented colonization of the lung, trachea and nose.

Current vaccines against whooping cough have serious disadvantages. Inactivated whole cell vaccines are relatively reactogenic resulting in reduced use in vaccination programs. Subunit vaccines on the other hand, have limited efficacy. This results in outbreaks of whooping cough, even in vaccinated populations. There are indications that an effective whooping cough vaccine should prevent colonization of the upper respiratory tract. Asymptomatic carriage facilitates spreading of the bacteria and a vaccine that prevents this could contribute to herd protection.

Intravacc scientists used a vaccine consisting of outer membrane vesicles (Intravacc’s OMV vaccine delivery platform) to immunized mice via the subcutaneous or intranasal route. Whereas subcutaneous immunization resulted in robust systemic immune responses of high quality, it could not prevent colonization of the nasal cavity. Intranasal immunization did not only induce excellent systemic responses but also strong local immune responses. Most importantly, intranasal administration prevented colonization of the lung, trachea and nose. Further testing, preferably in humans is needed to confirm these findings.