Virus World

Researchers hope as well as preventing disease the immunisation will, crucially, stop transmission of the virus. Spanish scientists are preparing to start clinical trials of a Covid-19 vaccine nasal spray that they say could stop the spread of the virus as well as prevent people from falling ill.  The vaccines that are currently available or close to approval, including the leading Pfizer/BioNTech jab, are all administered via injection, and while they are effective at preventing disease in someone who is infected with the virus, it is not yet clear if they stop people transmitting it. The Spanish team is one of a handful across the world working on nasal sprays as a means of delivering a vaccine. The theory is that inhalable vaccines activate the local immune response in the nose, mouth and throat and therefore stem infection here, making it less likely for people to pass the virus on. The vaccine would also deliver the wider systemic immunity that is delivered by any other candidate, the scientists say.

 

A team in China submitted approval for trials of a similar nasal spray vaccine in the autumn, and the team from Spain's CSIC national research council plan to begin human trials early next year.  Dr Luis Enjuanes, a virologist at the CSIC who has been studying coronaviruses for the past 40 years, told the Telegraph: "Where do we need the protection most? The virus is largely transmitted by us breathing in aerosols." Other leading experts said nasal sprays were a promising option.  "If you stick a needle into an arm and go straight into tissue you activate a whole different set of cells than if you inhale a vaccine through the nose,” said Deborah Dunn-Walters, professor of immunology at the University of Surrey and a spokesperson for the British Society for Immunology. "With a respiratory virus you have the nose, mouth and lungs which have mucosal surfaces and that's how the virus gets in. To stop the virus from getting to your cells you want the antibodies at the point at which it's meeting your cells so you can block it," she said.

 

Dr Enjuanes said his inhalable vaccine creates “a sterilising immunity, meaning there is no possibility for the virus to replicate”. Dr Enjuanes believes that the unique process his team is using will make their product “the most powerful”, claiming that the single-dose spray will offer “100 per cent protection” and pointing to good results so far in tests on mice. However, it will take time to get it to the market, he said.  “Because our system is completely new, the regulatory agencies will be asking for many more controls. That’s the reason we’ll be a little bit later, assuming we are lucky and there are no negative side-effects when we start testing on humans,” said Dr Enjuanes.