Intravacc’s experimental whooping cough vaccine shows promising results in a preclinical study

Intravacc, one of the leading translational research and development vaccine institutes with an extensive track record in developing viral and bacterial vaccines, announced promising results of a preclinical study with its experimental whooping cough vaccine in mice. Published in Scientific Reports (2020) 10:7396, the study shows 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.

Prof Dr Gideon Kersten, CSO of Intravacc, commented, “Intravacc’s vaccine concept has several potential advantages. Because of its composition outer membrane vesicles reduce the risk of vaccination induced selection of strains not matching with the vaccine, it induces immunity at the port of entry and it is needle free, allowing easy administration and flexible incorporation in immunization programs.”

Whooping cough, or pertussis, is a highly contagious respiratory disease that is caused by the gram-negative bacterium Bordetella pertussis and transmitted through Flügges droplets. It is a strictly human pathogen and all age groups can be infected. However, infants are the main risk group. Diagnosis of pertussis is often difficult in the early stage with only a mild cough, and fever is uncommon. Later, the severity of the disease increases with pneumonia, vomiting and increased coughing that in infants can lead to death.

Dr Jan Groen, CEO of Intravacc, said, “This study, showing full protection against whooping cough after intranasal immunization with our OMV based pertussis vaccine, provides us with a lot of comfort towards the development of our Covid-19 intranasal vaccine based on OMV’s”