key: cord-0711605-xh54u5sb
authors: Islam, Nazrul; Khunti, Kamlesh; Majeed, Azeem
title: COVID-19, seasonal influenza and measles: potential triple burden and the role of flu and MMR vaccines
date: 2020-11-11
journal: J R Soc Med
DOI: 10.1177/0141076820972668
sha: a14ded9f93bc754adca2c2b84e4d73c01b0b7886
doc_id: 711605
cord_uid: xh54u5sb

nan

number of cases and the need for hospitalisations for severe illnesses due to these diseases. It will, thereby, reduce the burden on healthcare providers and facilities, which will be particularly crucial in resource-poor settings in making the scarce resources (e.g. hospital beds) allocated to those who need them the most. A lower rate of hospitalisation from influenza and Measles-Mumps-Rubella will also help reduce the transmission of COVID-19 by decreasing the exposure to SARS-CoV-2 of the at-risk population, patients and their caregivers, such as parents of young children. 9 Second, live attenuated vaccines such as Measles-Mumps-Rubella and Bacillus Calmette-Gue´rin have been reported to provide non-specific protection against lethal infections including pneumonia and sepsis, especially in low-income settings. 10 The precise mechanisms by which these vaccine-related nonspecific protections work are not completely understood, but at least two mechanisms have been documented: vaccine-induced trained immunity and emergency granulopoesis (more technical details are available in Aaby et al. 10 ). Moreover, SARS-CoV-2 is a single-stranded positive-sense RNA virus, which shares similarity in structure with the yellow fever virus and murine Mengo virus. The Bacillus Calmette-Gue´rin vaccine was found to reduce the severity of infections due to yellow fever and murine Mengo viruses showing the potential that the Bacillus Calmette-Gue´rin vaccination may reduce COVID-19 severity as well. However, further empirical research is required to confirm the role of the Bacillus Calmette-Gue´rin and Measles-Mumps-Rubella vaccines on COVID-19 disease burden and outcomes.

Third, infection with measles has been shown to increase children's susceptibility to other infections by reducing the immune system's memory against other pathogens including the influenza virus. 11 Therefore, infection with measles may also increase the susceptibility to SARS-CoV-2 even though it is yet to be empirically tested. Nevertheless, an expanded Measles-Mumps-Rubella vaccine coverage will certainly reduce the number of cases with measles and potentially other diseases through nonspecific protection, as described above, and will decrease the exposure to SARS-CoV-2 for at-risk children and their parents by reducing the need for hospitalisations.

Therefore, as we wait for a successful vaccine for COVID-19, we can minimise winter pressures on health systems and societies by maximising the uptake of influenza and Measles-Mumps-Rubella vaccines (and potentially Bacillus Calmette-Gue´rin vaccines, especially in tuberculosis-endemic areas). It is to be noted that the proposal for expanding the vaccine coverage is for the intended purpose of protecting the at-risk population in which the vaccines have an established efficacy and safety profile. From the implementation perspectives, however, these actions come with some potential challenges. For example, uptake of the flu vaccine has often been low in younger at-risk patients (those aged <65 years) and among health and care staff in many countries, including the UK. 12 Even though many governments plan an expanded flu vaccination programme, the concurrent COVID-19 pandemic will make it challenging due to the need for good infection control (e.g. maintaining social distancing during the vaccination program, scarcity of personal protective equipment by the healthcare professional carrying out the vaccination campaign in resource-poor settings). Therefore, it is imperative that the planning for these vaccination programmes starts sooner to ensure a high coverage and uptake by the at-risk populations, including the healthcare providers. 

Contributorship: NI conceived the idea and consulted with KK and AM. NI wrote the first draft. KK and AM provided critical scholarly feedback. The final article was approved by all authors.

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