Flu vaccination for ex-preterms and infants under 6 months—are we getting it right?
- Newcastle Neonatal Services, Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Newcastle upon Tyne, UK
- Correspondence to Robert John Tinnion, Newcastle Neonatal Services, Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NE1 4LP, UK;
- Accepted 31 January 2010
Seasonal or pandemic flu causes illness and sometimes death, in vulnerable infants under 6 months old.1 2 Current UK and WHO guidelines recommend that only infants over 6 months receive any sort of flu vaccination, based on the lack of approval for the vaccines for infants under 6 months old, making its use in these infants “off-label”. However, WHO guidance is also clear that “at-risk” populations defined as “… certain chronic health conditions (such as chronic heart or lung disease, metabolic or renal disease or immunodeficiencies)” should be offered the seasonal flu vaccine.3 Some graduates of neonatal units are a high-risk population for flu infection once discharged into the community, but are often less than 6 months old. To date, there has been concern that non-adjuvanted, non-live vaccines were not sufficiently immunogenic to confer protection in infants less than 6 months old, but newer adjuvanted vaccines (including Pandemrix, GlaxoSmithKline, Middlesex, UK) are now available.
It has also been shown that ex-preterm infants with chronic lung disease when immunised at more than 6 months old with a trivalent inactivated flu vaccine can achieve and sustain protective concentrations of antibody4; however, there are few data on infants less than 6 months old. The limited evidence available in the neonatal population suggests that most (83%) infants less than 6 months old can mount a response considered protective to flu immunisation.5 Thus, younger infants are potentially being deprived an efficacious vaccine based on licensing issues, yet we do not allow such issues to prevent the use of other medication in these infants.6
Accordingly, our unit practice is to give the seasonal flu vaccine to high-risk infants (those with chronic lung disease, cardiac diagnoses and immune disorders) before discharge home. However, there is no national guidance for the use of flu vaccine in the neonatal intensive care unit population, and current guidance precludes the use of the pandemic flu vaccine in infants less than 6 months old.
Due to the lack of formal guidance and our concerns about withholding A/H1N1 vaccine from infants less than 6 months old, we conducted a telephone survey of 48 neonatal units in England and Scotland with six or more neonatal intensive care cots. Forty-five (93%) provided a response. Of these, 40 (88%) had a written guideline for immunisation of infants while inpatients on their neonatal unit and of these, 6 (15%) contained specific guidance regarding flu vaccination of infants on the unit. Infants offered flu vaccine in these units are shown in table 1. All the units with guidelines reported giving two 0.25 ml intramuscular doses separated by 1 month.
It appears that flu immunisation in at-risk infants in the UK is being undertaken off-label in several tertiary-level neonatal units, including our own. As flu is likely to remain a significant annual pathogen and the numbers of preterm infants surviving is increasing year-on-year, a properly organised, National Institute for Health Research-funded, multicentre study is needed urgently to confirm the safety and clarify the immunogenicity of flu vaccines in this at-risk group. Such a study would take time to provide clinically useful information. In the interim, other units may now feel enabled to offer flu immunisation given our own off-label usage, and we urge reconsideration of the current view that it is not appropriate to offer immunisation against pandemic flu to infants under 6 months of age.
Competing interests None.
Provenance and peer review Not commissioned; externally peer reviewed.