Herpes zoster vaccine and the risk of Bell's palsy and Guillain-Barre Syndrome in the UK

Date of ISAC Approval: 
23/05/2019
Lay Summary: 
The Zostavax vaccine was introduced in 2013 in the UK for prevention of shingles, a painful skin disease caused by herpes zoster virus. Shingles mostly affects people as they get older and particularly over the age of 70. Zostavax is licensed for those aged 50 and above and is offered free of charge to 70 year olds with vaccination available for those aged 79 to 71 who haven't been vaccinated yet. Shingles vaccines have been used in several countries, including the US and Canada. Previous studies have found that Zostavax is safe and well-tolerated. There have been a few cases of Bell's Palsy (a type of facial paralysis) and Guillain-Barre Syndrome (a neurological disorder causing weakness, numbness and pain of the feet, hands and limbs) reported following exposure to the vaccine via the Yellow Card Scheme to the Medicines and Healthcare products Regulatory Agency in the UK. However, both events occur naturally in the target population and so this study in the CPRD is designed to investigate if there is any association between Herpes Zoster vaccination and an increased risk of these two events. A self-controlled case series design will be used to analyse patients having received a diagnosis of one of these conditions and Herpes Zoster vaccination and compare their risk in exposed and non-exposed time windows. To our knowledge, this is the first study to investigate a potential association between Herpes Zoster vaccination and the risk of these conditions in the UK. The results of this study will be used to consider the need for future regulatory action.
Technical Summary: 
Herpes zoster vaccination programme was introduced in 2013 in England for prevention of shingles in adults aged 70 years with a phased catch-up programme for those aged 71-79 years. Shingles vaccines have been used in several countries, including the US and Canada. Previous studies have found that Zostavax is safe and well-tolerated. There have been a few cases of Bell's Palsy and Guillain- Barre Syndrome (GBS) reported to the MHRA following exposure to the vaccine. While this is not significantly more than expected, further exploration of the association between Zostavax and risks of Bell's palsy and GBS is considered important as there could be some potential plausibility for a causal association. In this study we will use general practice data linked to other datasets to investigate the potential association and temporal relationship between Zostavax vaccination and an increased risk of the occurrence of Bell's Palsy and GBS among 69-80 years old patients in the UK. Our study population will be patients 69-80 years old who experienced one of the outcomes of interest (GBS or Bell's Palsy) while their practice contributed up to standard records between 1st September 2013 and 31st of December 2018 either in GOLD or Aurum CPRD databases. Using a self-controlled case series design and conditional Poisson regression, the study will provide an estimate of the relative incidence for the two outcomes of interests in the pre-specified risk period post-vaccination compared to other (control) periods outside the specified vaccination risk windows. This will enable investigation of the potential for a causal association between Zostavax vaccine and an increased risk of the events reported through spontaneous reports.
Health Outcomes to be Measured: 
The events of interest include Bell's Palsy and Guillain-Barre Syndrome
Collaborators: 

Katherine Donegan - Chief Investigator - MHRA
Professor Nick Andrews - Collaborator - Public Health England
Dr Philip Bryan - Collaborator - MHRA
Stephanie Dellicour - Corresponding Applicant - MHRA

Linkages: 
HES Admitted