Reviewed by GPhC Pharmacist Ashley Cohen at Halton Pharmacy Clinical Team, Leeds , GPhC No. 1039734

Chickenpox is so strongly associated with childhood in the UK that most adults do not consider it a travel health risk. But a significant proportion of UK adults, estimated at around five to ten percent, are seronegative for varicella zoster virus (VZV) and therefore susceptible to primary infection.

Adult varicella is clinically distinct from the childhood disease:

• It is considerably more severe
• It carries a substantially higher risk of pneumonia, hepatitis, and encephalitis
• In certain groups, including pregnant women and immunocompromised individuals, it can be life-threatening

Travel to countries with different varicella epidemiology, or simply increased social contact with unvaccinated individuals abroad, can increase exposure risk.

Why Adult Varicella Is Clinically Different

In childhood, varicella (chickenpox) typically produces a self-limiting illness with widespread vesicular rash, fever, and malaise, resolving within seven to ten days with minimal complications in immunocompetent children.

The same virus in a susceptible adult produces a markedly different clinical picture. Adults with primary varicella are significantly more likely to develop:

• Varicella pneumonitis (chickenpox pneumonia), which can progress to respiratory failure
• Hepatitis
• Neurological complications, including encephalitis and cerebellar ataxia 

Hospitalisation rates for adult varicella are approximately ten times higher than for childhood varicella.

Who Is at Risk and Why

From 1st January 2026, varicella has been added to the routine childhood vaccinations in England through the MMRV vaccine. Prior to this, it was not included (unlike the USA, Canada, Australia, Germany, and many other countries).

This means:

• Adults in the UK who contracted chickenpox as children have natural immunity
• The five to ten percent who did not experience childhood infection remain susceptible

In adults born in the UK who do not recall childhood chickenpox, serology testing is a reasonable first step before vaccination. Adults born or raised in tropical and subtropical countries may also have lower rates of childhood VZV exposure and natural immunity compared to UK-born adults.

Specific High-Risk Groups for Travel

Pregnant Women

Varicella in pregnancy carries risk of:

• Fetal varicella syndrome (in the first 20 weeks, although highest risk is between weeks 13 and 20)
• Neonatal varicella (if infection occurs near delivery)
• Severe maternal pneumonitis

The varicella vaccine is a live vaccine and is contraindicated in pregnancy. Susceptible pregnant women should be counselled to avoid exposure and seek urgent medical assessment if exposed.

Immunocompromised Travellers

Primary varicella in immunocompromised patients can be life-threatening. This includes patients on:

• Immunosuppressants
• Biologics
• Chemotherapy
• Long-term high-dose corticosteroids 

Antivirals are available for most patients. Aciclovir dosed at 800mg four times a day from day seven to fourteen after exposure is recommended.

The Varicella Vaccine for Susceptible Adults

The varicella vaccine (Varivax or Varilrix in the UK) is a live attenuated vaccine given as two doses, four weeks apart. It is highly effective at preventing primary varicella or significantly reducing its severity.

In the UK, varicella vaccination is available on the NHS to:

• Susceptible adults in close contact with immunocompromised individuals (as part of infection control)
• Non-immune healthcare workers
• Those covered via the NHS childhood vaccination programme

Private varicella vaccination is also available, including at Halton Pharmacy in Leeds, for susceptible adults planning travel to destinations where exposure risk may be elevated.

Not sure if you’ve had chickenpox? Any adult who is unsure whether they had chickenpox as a child can have a varicella IgG antibody test to confirm their immune status before travel or before vaccination. Approximately 90 to 95 percent of UK adults who have no memory of chickenpox will test IgG positive, meaning they have natural immunity and do not require vaccination. The five to ten percent who test negative are genuinely susceptible and should be vaccinated before travel where possible.

Shingles (Herpes Zoster) and Travel

Shingles is a reactivation of latent VZV in individuals who have previously had chickenpox. Travel stress, UV exposure, physical exhaustion, and immunosuppression can all potentially trigger shingles reactivation.

Shingles is not directly transmissible to other adults as shingles, but it can transmit VZV to susceptible individuals via direct contact with active vesicular lesions  potentially causing chickenpox in a susceptible contact.

Immunocompetent adults with shingles should avoid direct contact with susceptible pregnant women, newborns, and immunocompromised individuals until all lesions have crusted.

This article is for general information only and does not constitute individual clinical advice. To discuss travel health at Halton Pharmacy on Selby Road, Leeds LS15 7JR, please book a travel health consultation.