What happens if I only receive 1 dose of the Shingrix (herpes zoster vaccine)?

Effectiveness of a Single Dose of Shingrix (Herpes Zoster Vaccine)

Receiving only one dose of Shingrix provides significantly less protection against shingles than the complete two-dose series, with single-dose effectiveness of approximately 57% compared to 70% with two doses. 1

Effectiveness of Single vs. Complete Dosing

• A large real-world observational study found that one dose of Shingrix provides approximately 56.9% effectiveness against herpes zoster, while completing the two-dose regimen increases effectiveness to 70.1% 1
• The complete two-dose series is strongly recommended for optimal protection against shingles and its complications 2
• Clinical trials demonstrated that the two-dose regimen of Shingrix provides over 90% efficacy in preventing herpes zoster in adults aged 50 years and older 3

Completion Rates and Timing

• Among people who receive a first dose of Shingrix, approximately 70% complete the two-dose series within six months, and 80% complete it within 12 months 4
• The recommended schedule for Shingrix is two doses administered 2-6 months apart 3
• Importantly, second doses administered beyond the recommended 6-month window still provide effective protection, so patients should be encouraged to complete the series even if delayed 1

Special Populations

• For immunocompromised adults aged ≥18 years, the second dose can be given 1-2 months after the first dose if they would benefit from a shorter vaccination schedule 2
• The two-dose effectiveness was not significantly lower for adults aged >80 years or for individuals with autoimmune conditions 1
• The vaccine remains effective among individuals with immunosuppressive conditions, though a complete two-dose series is particularly important for optimal protection in these populations 1

Barriers to Completion

• Concerns about vaccine tolerability are significantly associated with failure to complete the two-dose series 5
• Individuals concerned about side effects are 1.83 times more likely to receive only one dose rather than completing the full two-dose series 5
• Common side effects include injection-site reactions (pain, redness, swelling) and systemic symptoms, which are generally temporary 3

Clinical Recommendations

• If you've only received one dose of Shingrix, you should get the second dose as soon as possible, even if more than 6 months have passed since the first dose 1
• There is no need to restart the vaccination series if the interval between doses is longer than recommended 3
• Protection against shingles persists for at least 8 years with minimal waning when the complete two-dose series is administered 3

Prevention of Complications

• The two-dose regimen provides 76% effectiveness against postherpetic neuralgia, one of the most debilitating complications of shingles 1
• Without the second dose, you may have inadequate protection against both shingles and its potential complications 2, 1