2) The prophylaxis of specific sexually transmitted infections

i. Use of adult vaccinations and adult schedules

No adult hepatitis B vaccinations are licensed for use as per adult schedules in young people less than 16 years of age, but their use in sexual health services is common place.

ii. Use of adult vaccines in licensed modified schedules in 13 to 15 years of age

Some services may adopt an alternative ‘2 dose’ schedule for young people aged 13 to 15 yrs (incl), using 2 doses of Engerix B  20 micrograms at 0 and 6 months, but this is only suitable when there is a low risk of hepatitis B during the vaccination course and when completion of the 2 dose course can be assured¹.

The manufacturer of Engerix B also reports a reduced level of seroprotection at 42, 54 and 66 months in the 0, 6 schedule Engerix B 20microgram compared to 0,1,6 months of Engerix B 10 in 11 to 15 years old².

iii. Use of licensed paediatric vaccines in licensed schedules in 13-15 years of age

The vaccine should be offered early, preferably within 24 hours, and as post-exposure prophylaxis. It may be offered up to six weeks, but there is little to evidence to support its effectiveness beyond 14 days.

BASHH¹ recommends in young people that schedules can be:

• 0, 7, 21 days with a 4th dose at 12 months
• 0, 1, 2 months with a 4th dose at 12 months

The decision on the schedule should take into consideration the age of the child (super accelerated used extensively in sexual health services) and the risk of exposure.

Hepatitis B immunoglobulin should also be considered if the young person has been exposed to someone known to have hepatitis B and there are concerns they may be infectious. If indicated, hepatitis B immunoglobulin should ideally be given within 48 to 72 hours, but can be used for up to 7 days.

I. Pre-exposure prophylaxis (PrEP)

Some young people will be identified of being at increased risk of HIV through sexual exposure, e.g. young MSM, and appropriate advice should be sought from clinicians experienced in the prescribing of PrEP.

II. Post exposure prophylaxis sexual exposure (PEPSE)

Likewise, PEPSE maybe indicated in young people and appropriate advice should be sought. Decision should be made according to criteria in the appropriate National BHIVA guidelines for adult and CHIVA guidelines. PEPSE must be initiated as soon as possible, ideally within one hour but at least within 72 hours, with input from a specialist experienced in the prescribing of PEPSE.

All young people who are started on PEPSE should be assessed for continuation of PrEP post PEPSE and discussed with a clinician experienced in the prescribing of PrEP.

1. 1. BASHH National Guideline on the Management of Sexually Transmitted Infections and Related Conditions in Children and Young People (2021) [accessed 9 July 2024]
   2. Engerix B 20 micrograms/1 ml Suspension for injection [accessed 9 July 2024]