If someone received one dose of Shingrix (recombinant zoster vaccine) 2 years ago, do they need to repeat the whole series?

Shingrix Vaccination After Incomplete Series

If someone received only one dose of Shingrix (recombinant zoster vaccine) 2 years ago, they should receive the second dose as soon as possible to complete the series without restarting the entire series. 1, 2

Rationale for Completing the Series

The Advisory Committee on Immunization Practices (ACIP) and CDC guidelines clearly indicate that:

• The standard Shingrix vaccination schedule consists of two doses (0.5 mL each) administered 2-6 months apart 2
• There is no maximum interval between doses - if the second dose is delayed, it should still be administered as soon as possible without restarting the series 1
• Completing the full two-dose series is crucial for optimal protection 2, 3

Effectiveness of Complete vs. Incomplete Series

Real-world effectiveness data strongly supports completing the series:

• Two-dose effectiveness: 70.1% (95% CI, 68.6-71.5) 3
• One-dose effectiveness: 56.9% (95% CI, 55.0-58.8) 3

This significant difference in effectiveness (approximately 13% higher with two doses) underscores the importance of completing the full series, even when the second dose is delayed beyond the recommended 2-6 month interval.

Administration Guidelines

When administering the delayed second dose:

• No need to restart the series regardless of the time elapsed since the first dose 1
• Administer the second dose subcutaneously in the deltoid region 2
• The vaccine can be given simultaneously with other vaccines if needed (such as influenza or pneumococcal vaccines) 2

Special Considerations

Immunocompromised Patients

• For immunocompromised adults, a shortened dosing interval of 1-2 months between doses is recommended 2
• Even with delayed administration, the second dose remains effective in immunocompromised individuals 2

Previous Zoster Episode

• Having had a previous episode of herpes zoster is not a contraindication to completing the Shingrix series 1, 2
• In fact, vaccination is recommended to prevent future episodes once the acute episode has completely resolved 2

Common Pitfalls to Avoid

1. Restarting the series unnecessarily: There is no maximum interval after which the series must be restarted - simply administer the second dose as soon as possible 1

2. Assuming one dose provides sufficient protection: While one dose provides some protection (56.9% effectiveness), completing the series significantly improves effectiveness to 70.1% 3

3. Delaying the second dose indefinitely: Although there's no maximum interval, unnecessary delay should be avoided as the patient remains suboptimally protected until the series is completed 2

4. Confusing recommendations between Shingrix and the older Zostavax vaccine: Unlike the older live zoster vaccine (Zostavax), Shingrix requires two doses for optimal effectiveness 2, 4

In conclusion, for someone who received one dose of Shingrix 2 years ago, the clear recommendation is to administer the second dose as soon as possible without restarting the series, regardless of the extended interval since the first dose.