MHRA scientists test needle-free Strep A vaccine given through the nose
A study in mice, published in Human Vaccines & Immunotherapeutics, found that a vaccine delivered in the nose or under the tongue produced immune responses both in the airways and across the body.
Scientists at the UK medicines regulator have reported early progress on a Strep A vaccine that could be given without a needle, sprayed into the nose or placed under the tongue.
The work, by the Medicines and Healthcare products Regulatory Agency (MHRA) with the GSK Vaccines Institute for Global Health, was published in October in the peer-reviewed journal Human Vaccines & Immunotherapeutics. It was carried out in mice. No human trials have been announced.
Most group A streptococcus infections are mild, but serious complications can cause long-term disability or death. There is no licensed vaccine against the bacterium. The MHRA puts the global toll at more than 600 million infections a year and over 500,000 deaths from complications, with the heaviest burden in low and middle-income countries.
How the vaccine is built
According to the MHRA, most vaccine approaches concentrate on producing antibodies in the bloodstream. Strep A, though, gets its foothold on the mucosal linings of the nose and throat, and the team set out to build immunity there as well.
The candidate uses a carbohydrate from the Strep A bacterium, attached to a carrier made from GMMA, short for Generalised Modules for Membrane Antigens. These are tiny bubbles that bacteria shed naturally from their outer membrane. In this design they do two jobs: they carry the Strep A carbohydrate, and they act as an adjuvant, the ingredient that strengthens the immune response.
Given through the nose or under the tongue, the vaccine produced immune responses at the mucosal surfaces where infection starts and throughout the body, the MHRA said. The second matters for protection against the invasive forms of the disease.
Why delivery matters
The MHRA said the GMMA approach could support a new generation of affordable vaccines that are easier to give, which would widen access in the countries where Strep A does the most harm. It also pointed to antibiotics. Preventing infections in the first place would cut the number of courses prescribed, which helps slow the spread of resistance.
The regulator's laboratories carry out research on vaccine science, immunology and new ways of delivering vaccines, alongside its work licensing medicines. Any candidate would need to go through clinical trials before a licence could be sought.
