Older individuals in long-term care institutions (LTCIs) at risk of influenza may be infected by their healthcare workers. There are no accurate data on rates of laboratory-proven influenza in healthcare workers. Vaccinating healthcare workers against influenza may reduce infections acquired from this source. Because the signs and symptoms of influenza are similar to those of many other respiratory illnesses, it is important in studies testing the effects of influenza vaccination to prove by laboratory tests which are highly accurate whether residents in LTCIs actually have influenza or another respiratory illness.
Three randomised controlled trials (RCTs) (5896 participants) provided outcome data meeting our criteria. For risk of bias: randomisation was at low risk in two trials and unclear in one; allocation concealment and blinding in all three trials was unclear; incomplete outcome data in one trial was at low risk and in two at high risk; selective reporting all three trials was at low risk; performance bias (incomplete influenza vaccination of healthcare workers in the intervention arms) in all three trials was at high risk. No studies reported on adverse events. Vaccinating healthcare workers who care for those aged 60 or over in LTCIs showed no effect on laboratory-proven influenza or complications (lower respiratory tract infection, hospitalisation or death due to lower respiratory tract illness) in those aged 60 or over resident in LTCIs.
This review did not find information on other interventions used in conjunction with vaccinating healthcare workers (hand-washing, face masks, early detection of laboratory-proven influenza, quarantine, avoiding new admissions, prompt use of antivirals and asking healthcare workers with an influenza-like illness not to work.
There is no evidence that only vaccinating healthcare workers prevents laboratory-proven influenza or its complications (lower respiratory tract infection, hospitalisation or death due to lower respiratory tract infection) in individuals aged 60 or over in LTCIs and thus no evidence to mandate compulsory vaccination of healthcare workers. Other interventions, such as hand-washing, masks, early detection of influenza with nasal swabs, antivirals, quarantine, restricting visitors and asking healthcare workers with an influenza-like illness not to attend work, might protect individuals over 60 in LTCIs. High-quality randomised controlled trials testing combinations of these interventions are needed.