Experimental whooping cough vaccine confers broad protection

Intravacc, a translational research and development vaccine institute based in the Netherlands, has announced promising results for a preclinical study of its experimental whooping cough vaccine in mice, as published in the journal Scientific Reports.

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, but the severity of the disease later increases with pneumonia, vomiting and increased coughing that in infants can lead to death.

According to Intravacc, 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, which results in outbreaks of whooping cough even in vaccinated populations. There are indications that an effective whooping cough vaccine should prevent colonisation of the upper respiratory tract, thus limiting spread of the bacteria and contributing to herd protection.

Intravacc’s vaccine delivery platform is based on outer membrane vesicles (OMVs) — spherical vesicles with strong immunogenic properties — with the company’s scientists using an OMV-based whopping cough vaccine to immunise mice via the subcutaneous or intranasal route. But whereas subcutaneous immunisation resulted in robust systemic immune responses of high quality, it could not prevent colonisation of the nasal cavity. Intranasal immunisation, however, not only induced excellent systemic responses but also strong local immune responses. Most importantly, intranasal administration prevented colonisation of the lung, trachea and nose. Further testing, preferably in humans, is needed to confirm these findings.

“Intravacc’s vaccine concept has several potential advantages,” said Intravacc CSO Prof Dr Gideon Kersten. “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 immunisation programs.”

Earlier this month, Intravacc announced that it had signed a research service agreement to collaborate with US biotech company Versatope on a universal influenza vaccine based on the OMV platform. The company is also developing a COVID-19 intranasal vaccine based on OMVs.

Image credit: ©stock.adobe.com/au/Kateryna_Kon

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