Fatigue outcomes following an influenza virus pandemic: A systematic review and meta-analysis

ObjectivesFatigue is a pervasive clinical symptom for many infected with respiratory viruses such as influenza or coronaviruses. Prior evidence from influenza and coronavirus epidemics suggest that fatigue symptomology may continue beyond the acute phase, lasting for several months to several years post-discharge. This systematic review aimed to examine long-term fatigue prevalence among survivors and among communities, as well as investigate the current evidence for associated factors. DesignSystematic review and meta-analysis. SettingHospitalised and community samples. ParticipantsPatient populations with a confirmed diagnosis of a named influenza virus or coronavirus. Main outcomes measuredFatigue, fatigue syndromes ResultsTen studies met the inclusion criteria for a pooled prevalence analysis and five studies were identified as eligible for a means differences analysis. A fatigue prevalence of 41% (95% CI 0.299-0.488) was found among a total population of 1,310. Using the vitality subscale of the SF-36 as a proxy for fatigue, the estimate for means differences indicated a lower mean vitality score for survivors compared to population norms (M -1.523, CI -13.53 - 10.48), although this was not significant (p = 0.803). The most common associations with fatigue were PTSD, depression and anxiety, female gender and higher age. ConclusionsThis study reveals that a significant proportion of survivors (41%) experienced fatigue following their recovery from novel respiratory viruses such as SARS, MERS, SARS-CoV2 or influenza and that this fatigue can be long-lasting. Also, some factors such as female gender and psychological factors may contribute to continuing fatigue outcomes for this population. Strengths and limitations(a) this study provides support for long-term fatigue outcomes in people with a confirmed influenza, SARS, MERS, SARS-CoV2 virus infection (b) the study suggests individual, psychological and social factors are associated with fatigue, (c) findings are limited by the availability of fatigue data and lack of pre-morbid fatigue information; (d) a meta-analysis on the associations was prohibited by the small number of studies investigating long-term fatigue correlates and (e) the heterogeneity of the studies (>75%) suggests the pooled estimates should be interpreted with caution.