A measles-mumps-rubella (MMR) vaccine could be enhanced such that that it makes one immune to multiple variant strains of the Covid-causing virus, new research in animals suggests.
The resulting new vaccine could then confer immunity against measles, mumps and COVID-19, report scientists at The Ohio State University, US, calling it the "MMS" vaccine candidate - for Measles, Mumps and SARS-CoV-2.
In hamsters, antibodies against Covid induced by the MMS vaccine lasted at least four months without any sign of decline, they found.
Thus, the lifelong immunity against measles and mumps that an MMR vaccine confers could likely translate into prolonged protection against Covid in people vaccinated with the MMS, they said in their study published in the Proceedings of the National Academy of Sciences (PNAS) journal.
The new MMS vaccine, which would be delivered via the nose, is constructed by inserting a highly stable segment of the coronavirus spike protein into the existing MMR vaccine.
"The beauty here is we already know the MMR is used in children, so we're building on a 50-year safety record," said Jianrong Li, the study's senior author and a professor of virology at the university.
"We inserted three different spikes that allow broad neutralising antibodies to protect against the different variants of concern of SARS-CoV-2. It's quite promising, and would be a fantastic new type of vaccine to prevent COVID-19," said Li.
Further, in mice, the intranasal vaccine was found to protect the tissues lining the nose and lungs from damage and prevent disease symptoms such as weight loss.
The hamsters too showed a lack of clinical symptoms, only minor changes to tissue in the airways and undetectable levels of viral particles in the lungs.
The immunity from the MMS vaccine would be effective against the ancestral SARS-CoV-2 virus and two of its variants - Delta and Omicron, the scientists said.
"The MMS platform is also readily and rapidly adaptable to new variants such as Arcturus (XBB.1.16) and Eris (EG.5), which are currently circulating in the hum
an population," said co-first author Yuexiu Zhang, a graduate student in Li's lab.
Li said there were additional options to consider, including adding rubella back into the platform and, potentially inserting more spike proteins or other coronavirus proteins into the vaccine to further broaden protective immunity.
"We envision incorporating it into a routine immunisation program for children and to provide long-term immunity against COVID-19 for adults," he said.
