key: cord-0054220-1o3snsd0
authors: López-Martin, Inmaculada; Esteban, Eva Andrés; García-Martínez, Francisco Javier
title: Relationship between MMR Vaccination and Severity of COVID-19 Infection: a Survey among Primary Care Physicians
date: 2020-12-26
journal: Med Clin (Engl Ed)
DOI: 10.1016/j.medcle.2020.10.006
sha: 39756fcea87b507d1bcbdfeb276a92a951d80c3b
doc_id: 54220
cord_uid: 1o3snsd0

nan

The first epidemiological studies about the 2019 coronavirus disease (COVID-19) highlighted its low morbidity and mortality among children and young adults. Different hypotheses have speculated on the protective effect against COVID-19 exerted by an immunity trained by different vaccines, including the bacillus Calmette-Guerin (BCG), 1 hepatitis A, polio, and measles, mumps, and rubella (MMR) vaccines. 2 With a view to better characterize the relationship between the vaccination status and the severity of COVID-19, we designed a descriptive and observational study based on an anonymous survey administered to a population sample that included primary care physicians practicing in Madrid during the first wave of the pandemic. We would like to emphasize that this was an anonymous, confidential, unsponsored, and independent survey, which is why it did not have to be evaluated by an Ethics Committee. An invitation with a link to the SurveyMonkey survey platform was sent to each physician via WhatsApp between 20 April 2020 and 10 May 2020. The survey included questions about the demographics, vaccination status (MMR, BCG, and hepatitis B as a control), type of exposure, method used to diagnose infected patients, and severity of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The association between variables related to the vaccination status, viral infection, and severity of COVID-19 was analyzed using a chi-square test.

The information was collected from 208 survey responses provided by the participating primary care and emergency care physicians, of whom 148 were women, with a mean age of 47.15 (± 9.39) years and an age range of 29-65 years. The most relevant results of the survey are summarized in Table 1 .

After analyzing the results, we saw that there were no significant differences between the rate of SARS-CoV-2 infection for any of the vaccines. However, we did find statistically significant differences with respect to the severity of COVID-19 and the MMR vaccination status (p = 0.013). The MMR vaccine has been administered on a mandatory basis to all Spanish children in the context of the national vaccination program since 1981. In our study, most of the physicians infected with SARS-CoV-2 who had received the MMR vaccine (67.92%) presented with mild symptoms of COVID-19. None of those who had to be hospitalized due to COVID-19 remembered having received the MMR vaccine or having been immunized against any of the viruses included in this vaccine. No significant differences were observed with respect to the severity of COVID-19 and the BCG and hepatitis B vaccination status (p = 0.608 and 0.911, respectively). Some hypotheses link vaccination against MMR with an improved and faster innate immune response against This fact could explain the benign course of the disease in children and those under the age of 40 in our country. Other studies state that the MMR vaccine can induce neutralizing antibodies that cross-react with other viruses. 4 Cases have been described in which patients infected with SARS-CoV-2 generate cross-neutralizing antibodies against MMR. 5 The most remarkable limitations of this study are the low number of critically ill patients included in it and the fact that other risk factors were not analyzed in a multivariant analysis, as this was not the purpose of our research. With the publication of these results, we aim to draw the attention of the health authorities and research centers with a view for them to promote studies that will allow to confirm the existence of an association between MMR vaccination and a lesser severity of COVID-19. Until a safe and effective vaccine against SARS-CoV-2 is

Defining trained immunity and its role in health and disease

Rodríguez-Monroy F. Thirty-six COVID-19 cases preventively vaccinated with mumps-measles-rubella vaccine: all mild course

Online ahead of print

Protective effects of vaccinations and endemic infections on COVID-19: A hypothesis

Perspectives of Immune Therapy in Coronavirus Disease 2019

SARS-CoV-2 and EBV coinfection

Table 1. Results of the statistical analysis based on the severity of COVID-19

CoV-2 detected by reverse transcription polymerase chain reaction (rtPCR) and/or positivity for antibodies IgM and IgG

We would like to thank Dr. Ester Moreno Artero from the Dermatology Department of the Clínica Universidad de Navarra in Madrid, Spain, for her invaluable collaboration in the development of this study.

Agradecimientos A la Dra. Ester Moreno Artero del Departamento de Dermatología de la Clínica Universidad de Navarra de Madrid, por su colaboración indispensable en el desarrollo de este estudio.

The authors declare no conflict of interest.