The association between influenza vaccination and the risk of SARS-CoV-2 infection, severe illness, and death: a systematic review of the literature

Riccio, Marco Del; Lorini, Chiara; Bonaccorsi, Guglielmo; Paget, John; Caini, Saverio

doi:10.1101/2020.09.25.20201350

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…This lack of positive association persisted across the primary, secondary and all sensitivity analyses, many of which had high sample size. This adds to the evidence from other studies at individual level of no positive association between 2019‐20 influenza vaccination and COVID‐19 cases 15 …”

Section: Discussionsupporting

confidence: 70%

“…Conversely, several articles have been published in scientific journals on the negative association or no association between influenza vaccination and COVID‐19 mortality, hospitalisation and infection, 10,11 many of which are summarised in a recent systematic literature review 12‐15 . The authors of the latter paper recommend that further studies are carried out to validate these preliminary findings across settings.…”

Section: Introductionmentioning

confidence: 99%

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Absence of association between 2019‐20 influenza vaccination and COVID‐19: Results of the European I‐MOVE‐COVID‐19 primary care project, March‐August 2020

Kissling¹,

Hooiveld

Brytting

et al. 2021

Influenza Resp Viruses

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Background Claims of influenza vaccination increasing COVID‐19 risk are circulating. Within the I‐MOVE‐COVID‐19 primary care multicentre study, we measured the association between 2019‐20 influenza vaccination and COVID‐19. Methods We conducted a multicentre test‐negative case‐control study at primary care level, in study sites in five European countries, from March to August 2020. Patients presenting with acute respiratory infection were swabbed, with demographic, 2019‐20 influenza vaccination and clinical information documented. Using logistic regression, we measured the adjusted odds ratio (aOR), adjusting for study site and age, sex, calendar time, presence of chronic conditions. The main analysis included patients swabbed ≤7 days after onset from the three countries with <15% of missing influenza vaccination. In secondary analyses, we included five countries, using multiple imputation with chained equations to account for missing data. Results We included 257 COVID‐19 cases and 1631 controls in the main analysis (three countries). The overall aOR between influenza vaccination and COVID‐19 was 0.93 (95% CI: 0.66‐1.32). The aOR was 0.92 (95% CI: 0.58‐1.46) and 0.92 (95% CI: 0.51‐1.67) among those aged 20‐59 and ≥60 years, respectively. In secondary analyses, we included 6457 cases and 69 272 controls. The imputed aOR was 0.87 (95% CI: 0.79‐0.95) among all ages and any delay between swab and symptom onset. Conclusions There was no evidence that COVID‐19 cases were more likely to be vaccinated against influenza than controls. Influenza vaccination should be encouraged among target groups for vaccination. I‐MOVE‐COVID‐19 will continue documenting influenza vaccination status in 2020‐21, in order to learn about effects of recent influenza vaccination.

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Section: Discussionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Absence of association between 2019‐20 influenza vaccination and COVID‐19: Results of the European I‐MOVE‐COVID‐19 primary care project, March‐August 2020

Kissling¹,

Hooiveld

Brytting

et al. 2021

Influenza Resp Viruses

View full text Add to dashboard Cite

show abstract

“…Adjusted analyses for a large number of possible confounders, allowed by the high statistical power of our cohort, showed no excess risk of death alone, and death/ICU admission; however no protective effect for the most severe COVID19-related outcomes was suggested by our results. This finding is consistent with previous studies [ 13 , 23 , 24 ]. As in most of these studies, we cannot exclude a residual confounding of unregistered medical conditions associated with a worst prognosis in vaccinated people.…”

Section: Discussionsupporting

confidence: 94%

Association of Influenza Vaccination and Prognosis in Patients Testing Positive to SARS-CoV-2 Swab Test: A Large-Scale Italian Multi-Database Cohort Study

et al. 2021

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To investigate the association of the 2019–2020 influenza vaccine with prognosis of patients positive for SARS-CoV-2A, a large multi-database cohort study was conducted in four Italian regions (i.e., Lazio, Lombardy, Veneto, and Tuscany) and the Reggio Emilia province (Emilia-Romagna). More than 21 million adults were residing in the study area (42% of the population). We included 115,945 COVID-19 cases diagnosed during the first wave of the pandemic (February–May, 2020); 34.6% of these had been vaccinated against influenza. Three outcomes were considered: hospitalization, death, and intensive care unit (ICU) admission/death. The adjusted relative risk (RR) of being hospitalized in the vaccinated group when compared with the non-vaccinated group was 0.87 (95% CI: 0.86–0.88). This reduction in risk was not confirmed for death (RR = 1.04; 95% CI: 1.01–1.06), or for the combined outcome of ICU admission or death. In conclusion, our study, conducted on the vast majority of the population during the first wave of the pandemic in Italy, showed a 13% statistically significant reduction in the risk of hospitalization in some geographical areas and in the younger population. No impact of seasonal influenza vaccination on COVID-19 prognosis in terms of death and death or ICU admission was estimated.

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“…Some data indicate that influenza vaccination may have a favourable effect on COVID‐19 and its course. However, more studies are needed at this regard 45 …”

Section: Discussionmentioning

confidence: 99%

Impact that the COVID‐19 pandemic on routine childhood vaccinations and challenges ahead: A narrative review

et al. 2021

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Aim To document the decline in vaccination coverage in the first months of 2020 as an indirect effect of the COVID‐19 pandemic. Methods We performed a literature review in medical databases. Overall, 143 articles were initially retrieved, out of which 48 were selected and included in the review. Results Our review retrieved similar data in many countries worldwide, and, globally, preliminary data from the first 4 months of 2020 indicate a decline in diphtheria‐tetanus‐pertussis coverage, generally considered the marker of vaccination coverage across countries. World Health Organization recommends maintaining vaccination services, prioritising primary series vaccinations especially for measles‐rubella or poliomyelitis, but it also lets each country decide whether to maintain the immunisation services evaluating the current epidemiology of vaccine‐preventable diseases and the COVID‐19 local transmission scenario. Successively, recovering of vaccinations should be planned. Moreover, during the pandemic, influenza vaccination should be promoted as a central public health measure. Conclusion Future challenges will be to maintain the vaccination programmes, especially in children younger than 2 years old and adolescents, to plan the recovery of vaccinations for subjects who postponed them during the lockdown, and to early identify any vaccine‐preventable disease outbreak.

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The association between influenza vaccination and the risk of SARS-CoV-2 infection, severe illness, and death: a systematic review of the literature

Cited by 5 publications

References 20 publications

Absence of association between 2019‐20 influenza vaccination and COVID‐19: Results of the European I‐MOVE‐COVID‐19 primary care project, March‐August 2020

Absence of association between 2019‐20 influenza vaccination and COVID‐19: Results of the European I‐MOVE‐COVID‐19 primary care project, March‐August 2020

Association of Influenza Vaccination and Prognosis in Patients Testing Positive to SARS-CoV-2 Swab Test: A Large-Scale Italian Multi-Database Cohort Study

Impact that the COVID‐19 pandemic on routine childhood vaccinations and challenges ahead: A narrative review

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