Dr. Paul Fidel, Jr., from Louisiana State University Health – School of Dentistry and Professor Mairi Noverr from Tulane University School of Medicine propose the concept that administration of an unrelated live attenuated vaccine, such as the MMR (measles, mumps, rubella) vaccine, could serve as a preventive measure against the worst sequelae of COVID-19.
Air Force Tech Sgt. Joseph Anthony, medical technician with the 911th Aeromedical Staging Squadron, administers a vaccination to a member of the U.S. Army Reserve’s 336 Engineering Company Command and Control, Chemical Radiological and Nuclear Response Enterprise Team at the Pittsburgh International Airport Air Reserve Station, Pennsylvania, April 11, 2019. Image credit: Joshua J. Seybert, U.S. Air Force.
Mounting evidence demonstrates that live attenuated vaccines provide nonspecific protection against lethal infections unrelated to the target pathogen of the vaccine by inducing trained nonspecific innate immune cells for improved host responses against subsequent infections.
These vaccines induce nonspecific effects representing ‘trained innate immunity’ by training leukocyte (immune system cell) precursors in the bone marrow to function more effectively against broader infectious insults.
“Live attenuated vaccines seemingly have some nonspecific benefits as well as immunity to the target pathogen,” Dr. Fidel said.
“A clinical trial with MMR in high-risk populations may provide a low-risk-high-reward preventive measure in saving lives during the COVID-19 pandemic.”
“While we are conducting the clinical trials, I don’t think it’s going to hurt anybody to have an MMR vaccine that would protect against the measles, mumps, and rubella with this potential added benefit of helping against COVID-19.”
In a previous work, the researchers demonstrated that vaccination with a live attenuated fungal strain induces trained innate protection against lethal polymicrobial sepsis.
The protection was mediated by long-lived myeloid-derived suppressor cells (MDSCs) previously reported inhibiting septic inflammation and mortality in several experimental models.
“The MMR vaccine should be able to induce MDSCs that can inhibit or reduce the severe lung inflammation/sepsis associated with COVID-19. Mortality in COVID-19 cases is strongly associated with progressive lung inflammation and eventual sepsis,” the scientists said.
In direct support of the team’s concept, it was recently reported that the milder symptoms seen in the 955 sailors on the U.S.S. Roosevelt who tested positive for COVID-19 (only one hospitalization) may have been a consequence of the fact that MMR vaccinations are given to all U.S. Navy recruits
In addition, epidemiological data suggest a correlation between people in geographical locations who routinely receive the MMR vaccine and reduced COVID-19 death rates.
COVID-19 has not had a big impact on children, and the authors hypothesize that one reason children are protected against viral infections that induce sepsis is their more recent and more frequent exposures to live attenuated vaccines that can also induce the trained suppressive MDSCs that limit inflammation and sepsis.
They propose a clinical trial to test whether the MMR vaccine can protect against COVID-19, but in the meantime, they suggest that all adults, especially health care workers and individuals in nursing homes get the MMR vaccine.
“If adults got the MMR as a child they likely still have some level of antibodies against measles, mumps, and rubella, but probably not the myeloid-derived suppressor cells,” Dr. Fidel said.
“While the MDSCs are long-lived, they are not life-long cells. So, a booster MMR would enhance the antibodies to measles, mumps, and rubella and reinitiate the MDSCs. We would hope that the MDSCs induced by the MMR would have a fairly good life-span to get through the critical time of the pandemic.”
The team’s paper was published in the journal mBio.
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Paul L. Fidel Jr. & Mairi C. Noverr. 2020. Could an Unrelated Live Attenuated Vaccine Serve as a Preventive Measure To Dampen Septic Inflammation Associated with COVID-19 Infection? mBio 11: e00907-20; doi: 10.1128/mBio.00907-20
This article is based on a press-release provided by the American Society for Microbiology.
Source link: https://www.sci.news/medicine/live-attenuated-vaccines-covid-19-08559.html
