How does the flu vaccine have an affect on the risk of contracting COVID-19?

The coronavirus illness 2019 (COVID-19) is an acute respiratory condition that is induced by an infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As a final result of the swift transmission of SARS-CoV-2 and its superior morbidity and mortality fees, COVID-19 stays a significant danger.

Study: Does Influenza vaccination reduce the risk of contracting COVID-19? Image Credit: alessandro guerriero /

Review: Does Influenza vaccination decrease the possibility of contracting COVID-19? Picture Credit: alessandro guerriero /


In the beginning, the improvement of herd immunity the moment the vaccinated populace reached 70% was considered to lessen the transmission of SARS-CoV-2.

Nevertheless, the amount of vaccination in various nations varies relying on their precise economic predicament. As a consequence, developed nations around the world generally have a larger vaccination level as as opposed to underdeveloped international locations. This will increase the threat of prolonging the pandemic owing to the emergence of mutated strains of SARS-CoV-2.

Quite a few reports have noticed that the danger of infection and condition transmission are independent of finishing a COVID-19 vaccination regimen. While the threat of acquiring a serious infection is reduce in vaccinated folks, the transmission of SARS-CoV-2 variants involving vaccinated and unvaccinated people even now happens and can subsequently guide to the emergence of new variants.

Presently, 10 SARS-CoV-2 variants are getting monitored, two of which are thought of variants of issue (VOCs). Hence, there stays an urgent require to greater fully grasp the evolution of SARS-CoV-2, as perfectly as acquire novel solutions and preventive steps that mitigate its unfold and adverse effects on human wellness.

Former studies have assessed regardless of whether countermeasures utilized to guard towards other types of viruses could reduce the adverse results of COVID-19. Influenza and COVID-19 are two respiratory viral ailments that have equivalent modes of transmission, medical outcomes, hospitalizations, problems, and demise charges. On top of that, the transmission of these viruses frequently peaks for the duration of the wintertime months.

The most efficient strategy to reduce and control influenza epidemics is annual influenza vaccination. Similar vaccination campaigns have also been essential in controlling the COVID-19 pandemic.

The SARS-CoV-2 Omicron variant, which was to start with detected in South Africa on November 24, 2021, obtained at minimum 1 of its mutations from the common cold virus that was also existing in the same infected cell. The signs and symptoms of Omicron infection are also extremely similar to that of the common chilly.

Notably, flu vaccination has earlier been identified to lower intense care device (ICU) admissions, hospitalizations, and mortality from SARS-CoV-2 bacterial infections. On the other hand, such findings are contradictory and inadequate. More investigate is desired to improved have an understanding of the protecting purpose of the flu vaccine on COVID-19 infections.

A new Spanish research printed on the preprint server medRxiv* describes the association among the danger of contracting COVID-19 and the seasonal flu vaccine in individuals for whom the flu vaccine is advisable.

About the research

The current study included sufferers who were viewed as large-possibility for flu problems and had been, as a consequence, encouraged for vaccination. The clinical heritage of the clients was collected to acquire facts on COVID-19 diagnosis and flu vaccination.

Examine contributors residing in nursing households have been studied individually owing to distinct residing conditions. Equally trivalent and quadrivalent flu vaccines were being administered to the examine members.

The Mortality in tiny Spanish locations and Socioeconomic and Environmental Inequalities (MEDEA) deprivation index was utilised for the evaluation of well being inequalities and identification of areas with socioeconomic vulnerability. Details on the gender, age, chance components for flu vaccination, the incidence of COVID-19, and flu vaccine receipt ended up also gathered.

Research results

Out of the 429,537 analyze participants, about 45% were being vaccinated towards the flu, even though 56.8% were women of all ages. Members around the age of 80 were being most probably to be vaccinated. Also, about 4% of vaccinated people today and 4.44% of unvaccinated men and women contracted COVID-19.

Individuals with risk elements for flu issues, this kind of as those people with cardiovascular disorders, lung troubles, diabetic issues mellitus, and kidney problems, who also obtained the flu vaccine ended up at a reduced threat of contracting COVID-19.

Probability of contracting COVID-19 depending on whether or not the patient had received the flu vaccine. Probability of contracting COVID-19 dependent on whether or not or not the affected individual experienced obtained the flu vaccine.

Substantial MEDEA values ended up related with lower vaccination premiums and a higher chance of COVID-19. On top of that, at significant MEDEA index values, persons below 60 decades of age ended up affiliated with larger COVID-19 incidence charges as as opposed to individuals around the age of 60.


The present study demonstrates that the flu vaccine could decrease the danger of COVID-19 amongst folks who are at higher threat for flu troubles. Even so, continuous and powerful immunizations are expected to minimize the stress of respiratory conditions, particularly for the duration of a period in which influenza and COVID-19 overlap.

Further more investigate is essential to acquire preventive approaches in opposition to both equally illnesses simultaneously, as there is a large chance of living with both of those viruses for a very long time.

*Vital detect

medRxiv publishes preliminary scientific reviews that are not peer-reviewed and, for that reason, need to not be regarded as conclusive, manual medical observe/health and fitness-relevant conduct, or taken care of as set up info.

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