Annual influenza vaccination effect  on the susceptibility to COVID-19 infection

Erismis, Betul; Jouanguy, Emmanuelle; Ekşi, Fatma; Karandere, Faruk; Dogan, Belgin; Okay, Fatih; Filiz, Melih; Koçoğlu, Hakan; İşsever, Halim; Hurşitoğlu, Mehmet; Yaşar, Kadriye Kart

doi:10.21101/cejph.a6573

Cited by 13 publications

(18 citation statements)

References 7 publications

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“…The findings also corroborate findings of studies that found similar protective effects for influenza vaccination [3][4][5][6][7][8][9][10][11][12] , though other studies did not 40,41 . These findings may be explained by influenza vaccination triggering a nonspecific immune activation, or trained or bystander immunity that is protective against SARS-CoV-2 infection [3][4][5]7,[42][43][44][45][46][47] .…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of influenza vaccination against SARS-CoV-2 infection among healthcare workers in Qatar

Tayar

Abdeen

Alah

et al. 2022

Preprint

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A number of studies reported that influenza vaccination is associated with lower risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and/or coronavirus disease 2019 (COVID-19) morbidity and mortality. We conducted a matched, test-negative, case-control study to estimate effectiveness of influenza vaccination, using Abbott’s quadrivalent Influvac Tetra vaccine, against SARS-CoV-2 infection and against severe COVID-19. The study was implemented on a population of 30,774 healthcare workers (HCWs) in Qatar during the 2020 annual influenza vaccination campaign, between September 17, 2020 and December 31, 2020, before introduction of COVID-19 vaccination. The median age in the matched samples was 36 years (interquartile range (IQR), 32-44) for cases and 35 years (IQR, 32-42) for controls. The median duration between influenza vaccination and the PCR test was 43 days (IQR, 29-62). The estimated effectiveness of influenza vaccination against SARS-CoV-2 infection >14 days after receiving the vaccine was 29.7% (95% CI: 5.5-47.7%). The estimated effectiveness of influenza vaccination against any severe, critical, or fatal COVID-19 was 88.9% (95% CI: 4.1-98.7%). Sensitivity analyses confirmed main analysis results. Recent influenza vaccination is associated with an appreciable reduction in the risk of SARS-CoV-2 infection and COVID-19 severity.

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Section: Discussionmentioning

confidence: 99%

Effectiveness of influenza vaccination against SARS-CoV-2 infection among healthcare workers in Qatar

Tayar

Abdeen

Alah

et al. 2022

Preprint

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“…Recently, several studies have suggested a possible protective effect of the influenza vaccine against SARS-CoV-2 [9][10][11][12]. Although no cross-reactivity between influenza-induced antibodies and SARS-CoV-2 protection has been demonstrated, several theorized mechanisms of the potential protective effect of influenza vaccination have been proposed in the recent literature [9,13,14].…”

Section: Introductionmentioning

confidence: 99%

Examining the potential benefits of the influenza vaccine against SARS-CoV-2: A retrospective cohort analysis of 74,754 patients

et al. 2021

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Introduction Recently, several single center studies have suggested a protective effect of the influenza vaccine against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This study utilizes a continuously updated Electronic Medical Record (EMR) network to assess the possible benefits of influenza vaccination mitigating critical adverse outcomes in SARS-CoV-2 positive patients from 56 healthcare organizations (HCOs). Methods The de-identified records of 73,346,583 patients were retrospectively screened. Two cohorts of 37,377 patients, having either received or not received influenza vaccination six months–two weeks prior to SARS-CoV-2 positive diagnosis, were created using Common Procedural Terminology (CPT) and logical observation identifiers names and codes (LOINC) codes. Adverse outcomes within 30, 60, 90, and 120 days of positive SARS-CoV-2 diagnosis were compared between cohorts. Outcomes were assessed with stringent propensity score matching including age, race, ethnicity, gender, hypertension, diabetes, hyperlipidemia, chronic obstructive pulmonary disease (COPD), obesity, heart disease, and lifestyle habits such as smoking. Results SARS-CoV-2-positive patients who received the influenza vaccine experienced decreased sepsis (p<0.01, Risk Ratio: 1.361–1.450, 95% CI:1.123–1.699, NNT:286) and stroke (p<0.02, RR: 1.451–1.580, 95% CI:1.075–2.034, NNT:625) across all time points. ICU admissions were lower in SARS-CoV-2-positive patients receiving the influenza vaccine at 30, 90, and 120 days (p<0.03, RR: 1.174–1.200, 95% CI:1.003–1.385, NNT:435), while approaching significance at 60 days (p = 0.0509, RR: 1.156, 95% CI:0.999–1.338). Patients who received the influenza vaccine experienced fewer DVTs 60–120 days after positive SARS-CoV-2 diagnosis (p<0.02, RR:1.41–1.530, 95% CI:1.082–2.076, NNT:1000) and experienced fewer emergency department (ED) visits 90–120 days post SARS-CoV-2-positive diagnosis (p<0.01, RR:1.204–1.580, 95% CI: 1.050–1.476, NNT:176). Conclusion Our analysis outlines the potential protective effect of influenza vaccination in SARS-CoV-2-positive patients against adverse outcomes within 30, 60, 90, and 120 days of a positive diagnosis. Significant findings favoring influenza vaccination mitigating the risks of sepsis, stroke, deep vein thrombosis (DVT), emergency department (ED) & Intensive Care Unit (ICU) admissions suggest a potential protective effect that could benefit populations without readily available access to SARS-CoV-2 vaccination. Thus further investigation with future prospective studies is warranted.

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“…Most studies enrolled individuals from the general population. Among them, five studies had as a population study health workers [26–30], one study involved only pregnant women [31], another study included only transplant recipients [32] and four studies were performed in older adults (age >65) [33–36]. The laboratory method (rt-PCR) used to diagnose of the disease was common in most of the included studies.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, two studies (Debisarum et al [37], Erismis et al [30]) were scrutinized further as in their analysis they used only age and sex, respectively as adjustment variables. However, when both were excluded from the meta-analysis and the overall meta-analysis was repeated, the results did not differ from the overall estimate: OR 0.81 (95% CI: 0.75-0.87).…”

Section: Resultsmentioning

confidence: 99%

“…This association is counter-intuitive at first sight and hence needs to be explained. It is worth mentioning that BCG vaccine, a vaccine primarily used against tuberculosis (TB), which is mandatory in several countries [30], seems also to has a protective effect since a meta-analysis of data from 160 countries has shown that when the BCG vaccine coverage was over 70% there was a reduction in the COVID-19 infections [12]. Also some studies have found that mandatory BCG vaccination is associated with a flattening of the curve in the spread of COVID-19 [46] and that differences in mortality produced by COVID-19 across countries are correlated with a country’s BCG vaccination policy [47, 48].…”

Section: Discussionmentioning

confidence: 99%

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Influenza and pneumococcal vaccination and the risk of COVID-19: A systematic review and meta-analysis

Kapoula

Vennou

Bagos

2022

Preprint

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A number of studies have investigated the potential non-specific effects of some routinely administered vaccines (e.g. influenza, pneumococcal) on COVID-19 related outcomes, with contrasting results. In order to elucidate this discrepancy, we conducted a systematic review and meta-analysis to assess the association between seasonal influenza vaccination and pneumococcal vaccination with SARS-CoV-2 infection and its clinical outcomes. PubMed and medRxiv databases were searched, up until November 2021. Random effects model was used in the meta-analysis to pool odds ratio (OR) and adjusted estimates with their 95% confidence intervals (CIs). Heterogeneity was quantitatively assessed using the Cohran's Q and the I2 index. Sub-group analysis, sensitivity analysis and assessment of publication bias were performed for all outcomes. In total 38 observational studies were included in the meta-analysis and there was substantial heterogeneity. Influenza and pneumococcal vaccination were associated with lower risk of SARS-Cov-2 infection (OR: 0.80, 95% CI: 0.75-0.86 and OR: 0.70, 95% CI: 0.57-0.88, respectively). Regarding influenza vaccination, it seems that the majority of studies did not properly adjust for all potential confounders, so when the analysis was limited to studies that adjusted for age, sex, comorbidities and socioeconomic indices, the association diminished. This is not the case regarding the pneumococcal vaccination, for which even after adjustment for such factors the association persisted. Regarding harder endpoints such as ICU admission and death, current data do not support the association. Possible explanations are discussed, including trained immunity, inadequate matching for socioeconomic indices and possible coinfection.

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Annual influenza vaccination effect on the susceptibility to COVID-19 infection

Cited by 13 publications

References 7 publications

Effectiveness of influenza vaccination against SARS-CoV-2 infection among healthcare workers in Qatar

Effectiveness of influenza vaccination against SARS-CoV-2 infection among healthcare workers in Qatar

Examining the potential benefits of the influenza vaccine against SARS-CoV-2: A retrospective cohort analysis of 74,754 patients

Influenza and pneumococcal vaccination and the risk of COVID-19: A systematic review and meta-analysis

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