Intended for healthcare professionals


Influenza vaccination in healthcare professionals

BMJ 2012; 344 doi: (Published 28 March 2012) Cite this as: BMJ 2012;344:e2217
  1. Harish Nair, research fellow1,
  2. Alison Holmes, professor of infectious diseases2,
  3. Igor Rudan, professor of international health and molecular medicine1,
  4. Josip Car, director3
  1. 1Centre for Population Health Sciences, Global Health Academy, University of Edinburgh, Edinburgh, UK
  2. 2National Centre for Infection Prevention and Management (CIPM), Department of Medicine, Imperial College, London, UK
  3. 3Global eHealth Unit, Department of Primary Care and Public Health, School of Public Health, Imperial College, London W6 8RP, UK

Should be mandatory

There is clear evidence that healthcare workers play an important role in transmitting infections to their patients.1 The World Health Organization and national immunisation guidelines in 60% of developed and emerging economies strongly recommend annual vaccination against seasonal influenza for all healthcare workers in acute and long term care facilities.2 However, unlike other prophylactic measures targeted at healthcare workers, such as hepatitis B vaccination, the uptake of flu vaccine has been generally poor. In the United States, two decades of consistent advocacy by the Centers for Disease Control and Prevention achieved a self reported vaccine coverage of only 64% among healthcare workers by 2010-1.3 In the United Kingdom, despite recommendations by the Department of Health, uptake of seasonal flu vaccine was a dismal 35% among frontline healthcare workers in the same year.4

Flu contributes greatly to global mortality and morbidity and has important economic consequences. Each year, seasonal flu affects 5-10% of the world’s population, causing 3-5 million severe infections and resulting in 250 000-500 000 deaths. Young children (especially those under 1 year); pregnant women; people over 65 years (especially those in institutional care); people with chronic medical conditions such as diabetes, asthma, chronic obstructive pulmonary disease, and chronic kidney disease; and those who are obese or immunocompromised are at a higher risk of severe influenza and associated mortality. These vulnerable patient groups are also at high risk of acquiring nosocomial flu infections and have a high case fatality rate.1

The reasons for low vaccine uptake among healthcare workers are manifold and none is supported by current scientific evidence. Firstly, many healthcare workers believe that they are not at risk of contracting flu. However, observational research has shown that even in a mild epidemic season about 23% of healthcare workers had serological evidence of flu, with 28-59% of these infections being subclinical.5 Furthermore, most healthcare workers continue to care for their patients when ill, which increases the probability of nosocomial transmission.6 Nosocomial flu infections have a high case fatality rate of 27%, especially in patients with comorbidities.7

Secondly, some believe that vaccinating healthcare workers with trivalent inactivated vaccine has no significant effect on nosocomial flu infection and its outcome (morbidity and mortality) in the vulnerable group of patients most likely to acquire flu. A review that found no significant difference in laboratory confirmed outcomes in elderly patients in long term care facilities may be responsible for this belief.8 However, all studies included in the review were limited by several biases and strain mismatch between the vaccine and circulating virus. Studies from temperate and tropical regions have shown that vaccinating healthcare workers against flu reduces flu infections and sickness leave for flu-like illnesses, with the difference being significant when the vaccine strains and circulating strains are well matched.9 10

Finally, many healthcare workers refuse the vaccine because they are not convinced that it is safe and they fear adverse effects. However, good evidence shows that the trivalent inactivated vaccine is safe and has a vaccine effectiveness of 70-90% in the presence of a good strain match between the circulating and vaccine virus strains. A recent meta-analysis reported similar results for the pandemic vaccine.11 The authors estimate that in the absence of a good strain match the efficacy ranges from 59% to 83%, depending on the type of vaccine used.

Recommendations by health authorities and promotional campaigns for flu vaccination only marginally increase vaccine uptake by healthcare workers.12 In light of accumulating evidence that flu vaccination in healthcare workers is an effective and useful strategy, there is therefore a strong case for mandating vaccination in healthcare workers who are in direct contact with patients. All healthcare workers should strive to “first do no harm.” If vaccination can prevent harm to patients there is a clear ethical and legal argument that workers should be vaccinated. Moreover, employers are ethically bound to protect their staff from hospital acquired infections. There is also an economic case for vaccinating healthcare workers.12 It is pointless to have a policy without the will to mandate it in the interest of patients. Adverse events are always possible after flu vaccination, and resistance to a mandatory vaccination policy is probably inevitable. However, 98% coverage has been achieved in the US among healthcare workers whose employers require compulsory flu vaccination,3 and minor adverse reactions have been reported in less than 1% of vaccine recipients in the general population, similar to adverse events for other vaccines.

Although good quality studies (such as randomised controlled trials of a vaccine with a good strain match over several years in different settings) are still needed to firmly establish that vaccinating healthcare workers prevents nosocomial flu in patients, the current policy of strongly recommending annual flu vaccination to healthcare workers cannot continue. The English Department of Health needs to make flu vaccination mandatory in all healthcare workers who have direct contact with patients.


Cite this as: BMJ 2012;344:e2217


  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Provenance and peer review: Not commissioned; peer reviewed.


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