shown to protect mice ferrets hamsters and monkeys against the coronavirus a new study last week offered powerful evidence in support of their use as a boosteran intranasal booster induced immune memory cells and antibodies in the nose and throat and strengthened protection from the initial vaccination the researchers reported the study has not yet been published in a scientific journalour approach is to not use a nasal vaccine as a primary vaccination but to boost with nasal vaccine because then you can leverage the existing immunity thats already created said akiko iwasaki an immunologist at yale university who led the studywhen she and her colleagues used a mix of proteins from the new coronavirus as well as the related sars virus their experimental nasal vaccine seemed capable of fending off a broad range of coronavirus variantstheres some flexibility and there might be more resilience against the virus said dr gommerman who was not involved in the work and because we dont know what the virus will do next thats awfully appealingthe current covid vaccines are injected into muscle and excel at training immune cells to tackle the virus after it enters the body they produce antibodies called igg that circulate in the blood and can be marshaled when neededbut few of these antibodies travel to the nose and throat and even those that do wane quicklyby contrast nasal vaccines produce a special set of antibodies called iga that thrive on mucosal surfaces like the nose and throat and these antibodies may wane more slowlya vaccine delivered with a nebulizer could coat the entire airway including the lungs with iga antibodies its not just the tip of the nose thats protected dr iwasaki saidmounting evidence supports iga antibodies as the key to preventing infection in one study dr gommerman and her colleagues found that only about 30 percent of people had detectable iga antibodies after receiving a second dose of vaccinethose who had lower levels of iga within a month of the second dose were more likely to develop a breakthrough infection igg levels seemed to have no impact on the outcomelocation really matters and mucosal immunity is really important for protection from infection said michal tal an immunologist at stanford university who was involved in the workimagecreditpallava baglacorbis via getty imagespeople who gain immunity because of an infection with the virus rather than from an injected vaccine tend to have strong mucosal immunity at least for a while that may help explain why they seemed to fare better against the delta variant than those who had been vaccinated dr tal saidbut she warned that trying to obtain mucosal immunity by getting infected was dangerous the way to get people that kind of mucosal protection really really really should be with a nasal vaccine she saidinjected vaccines are the right approach for generating the systemic immunity needed to prevent death and disease the urgent goal at the start of the pandemic dr tal said and the trump administration ushered in