Pneumococcal infection is notifiable in the UK and is rare in paediatric coeliac disease (CD) patients¹. Vaccination in the UK began in 2006 with the conjugate vaccines PCV-7 in 2006 and PCV-13 (Prevenar) from 2010, given at 2, 4 and 12 months and now a two-dose schedule (from 2020). The COVID-19 crisis escalated parental and healthcare concern about viral infections, subsequent risk of secondary infection, underlying risk of hyposplenism and pneumococcal immunisation and its role in reducing infection. We looked at vaccine response in a group of paediatric coeliac disease patients to help alleviate those concerns.

Consecutive patients attending for CD follow-up at a regional tertiary service in Scotland had pneumococcal antibody levels measured as part of their routine blood monitoring and standard care. Electronic records of these patients were retrospectively reviewed to identify immunisation dates, potential episodes of pneumococcal infection, positive microbiology or evidence of hyposplenism.

46 (73%) were female. Median age at CD diagnosis was 9 years. Median time from immunisation to CD diagnosis was 6.5 years (range -3 to 14 years). Six patients (born before 2006) had never received immunisation. No patients had antibody levels less than 20 units/ml.

Pneumococcal antibodies were measured in 63 patients from July 2020 to February 2021. 46 (73%) were female and median age at CD diagnosis was 9 years. Median time from immunisation to CD diagnosis was 6.5 years. The lowest antibody level was 21 units/ml and there was no significant difference in antibody level between children who had received 0, 1, 2 or 3 doses of immunisation. No patients had hospital presentations or positive microbiology samples suggestive of pneumococcal infection and none had evidence of hyposplenism.

All patients had levels above 20 units/ml (this represents a ‘protective level’ in unimmunised and PPV-23 immunised patients). The protective level post PCV-13 immunisation is unknown. We assume (as with the general population) that lifelong immunity develops and boosters should not be required. Immune memory theoretically should be better with conjugate vaccines, but longer-term antibody response in CD has not been definitively investigated. It is currently recommended that unimmunised CD patients receive PPV-23 (Pneumovax) then lifelong 5-yearly boosters² despite ‘hyposplenism’ affecting 30% of adult CD patients at most. Uptake and understanding of the optimal schedule is poor in the CD community. Further detailed evaluation of vaccination response for CD patients is required for clarity of patient protection and avoidance of potentially unnecessary and expensive immunisations.

References

1. Corazza GR, Lazzari R, Frisoni M, et al. Splenic function in childhood coeliac disease. Gut 1982;23:415–416.

2. Immunisation against infectious disease – The Green Book. London, PHE, 2020. Chapter 25: Pneumococcal.