BPSU study - Congenital and Hospitalised Neonatal Varicella

BPSU surveillance of fetal varicella syndrome (FVS) and neonatal varicella is to commence with the June 2023 card. The study is conducted by the UKHSA and led by Dr Gayatri Amirthalingam, and will study how many babies have FVS or neonatal varicella, the features of the diseases, the treatments babies receive and the outcomes of their disease. This study aims to understand FVS and neonatal varicella in order to guide decisions about chicken pox vaccination, and to guide the treatment of these conditions. A parallel study will be conducted in Portugal.

Lead investigator

Dr Gayatri Amirthalingam
Consultant Medical Epidemiologist, Immunisation and Vaccine Preventable Diseases Division
Deputy Director, Public Health Programmes
UK Health Security Agency, 61 Colindale Avenue, London, NW9 5EQ 


About the study

Chickenpox (varicella) is a common childhood infection which most individuals in European countries, such as the United Kingdom, will have contracted by the time they are teenagers. Although it is often mild, severe chickenpox is more likely in young babies, pregnant women and those with poorly functioning immune-systems.

Chickenpox can be particularly devastating if contracted during pregnancy as the infection can be passed to the developing baby increasing the likelihood of stillbirth and premature birth. Chickenpox acquired in this way is known as fetal varicella syndrome (FVS). FVS can cause problems with the way an infant learns and develops. Many children with FVS have lifelong health consequences, including limb problems, learning disabilities and visual impairment. Babies who contract chickenpox in the first month of life, known as neonatal varicella, are also vulnerable to severe consequences. These can include breathing difficulties and brain infection, as their immune systems are still developing. Due to the severity of the condition in young babies, most babies that catch the virus in the first month of life will be admitted to hospital rather than receiving care from their General Practitioner.

A safe and effective chickenpox vaccine has been developed but it has not been implemented as part of the UK routine immunisation programmes. Important information is lacking regarding the burden of severe chickenpox especially fetal varicella infection (FVS) and infection in the first month of life (hospitalized neonatal varicella), as this data is not routinely collected. This information is crucial to guide decisions about the benefits and cost effectiveness of introducing the chickenpox vaccine.

This study aims to collect data on fetal varicella syndrome and babies hospitalized with neonatal varicella infections over a 13-month surveillance period. Notifying clinicians will be directed to the online questionnaire via the dedicated BPSU online platform. The crucial information gained from this study will help inform public health interventions in the UK, could guide decisions regarding introducing a routine chickenpox vaccine, and will help design treatment and management of babies with these rare but devastating conditions.

Case definition

Fetal varicella syndrome:

1a) Any stillborn or liveborn infant who, in the opinion of the notifying paediatrican, has confirmed or suspected fetal varicella syndrome, with or without congenital deformities based on history, clinical and/or laboratory findings.

1b) Any infant that presents with herpes zoster (shingles) in the first year of life (based on clinical and laboratory findings)

1c) Spontaneous abortion or termination of pregnancy following varicella in pregnancy.

Neonatal varicella syndrome:

1) Chicken pox in an infant less than one month of age, regardless of gestational age at birth, based on history, clinical findings and/or laboratory findings.

Reporting instructions

Please report any liveborn infant, stillbirth or termination of pregnancy that, in your opinion, had fetal varicella infection. This will include any infant less than a year old who develops shingles. Please also report cases of varicella diagnosed in the first 28 days of life.  Please report all suspected cases, even if the results of investigations are pending.


BPSU surveillance will be undertaken for 13 months, commencing with the June 2023 card.


Funding for this study is provided by the European Society for Paediatric Infectious Diseases (ESPID) and the International Network of Paediatric Surveillance Units (INOPSU)’s Surveillance Research Grant.


The study was approved by the Research Ethics Committee and the Health Research Advisory Group (England and Wales) (REC Reference 22/SW/0040; IRAS project ID 277788), the Public Benefit and Privacy Panel (Scotland), the Privacy Advisory Committee (Northern Ireland) and has been granted Section 251 HRA-CAG permission (CAG reference: 22/CAG/0040).

Privacy notice

UKHSA is the sponsor and data controller for this research study. Any governance concerns can be directed to the UKHSA Data protection officer at data_protectionofficer@dhsc.gov.uk

If you want access to the information in your child’s NHS records, then you should contact your child’s NHS hospital/doctor. 

You must tell your doctor or hospital if you do not want your records to be used. More information can be found at: https://www.hra.nhs.uk/information-about-patients/

Individuals living in England can register a national data opt out. Registering an opt out means that none of your child’s NHS information relating to care provided in England would be used for research or planning - visit the NHS website page, Choose if data from your health records is shared for research and planning or call 0300 303 5678. Families can also opt-out of having their medical information used for research by informing their attending clinician. For individuals living in Scotland and Northern Ireland, please inform the doctor treating your child for FVS/neonatal varicella if you do not want them to be included in this study

If you wish to complain about the use of your personal information, then you should contact the Information Commissioner’s Office:

Information Commissioner’s Office
Wycliffe House
Water Lane
Cheshire SK9 5AF

Helpline number: 0303 123 1113
Email: casework@ico.org.uk

Support group

Supported by Bliss, the leading UK charity for babies born needing neonatal care. For babies born premature or sick | Bliss