Safety of Waiting 2 Years Between Shingrix Doses
While waiting 2 years between Shingrix doses is not ideal, it is still safe and effective to complete the series even after this extended interval.
Recommended Dosing Schedule
The standard recommended schedule for Shingrix (recombinant zoster vaccine) is:
- For immunocompetent adults ≥50 years: Two doses administered 2-6 months apart 1
- For immunocompromised adults ≥18 years: Two doses administered 1-2 months apart 1
Extended Interval Evidence
Research supports the effectiveness of Shingrix even with extended intervals between doses:
- A Phase III clinical trial specifically evaluated different dosing intervals and found that immune responses to Shingrix administered at a 0,6-month schedule were non-inferior to those elicited by the standard 0,2-month schedule 2
- While the same study found that the 0,12-month schedule did not meet the non-inferiority criterion, it still demonstrated a robust immune response with a vaccine response rate of 94.5% 2
- Real-world effectiveness data shows that second doses administered beyond the recommended 6 months did not significantly impair effectiveness 3
Importance of Completing the Series
Completing the full two-dose series is crucial for optimal protection:
- Two-dose effectiveness is significantly higher (70.1%) compared to single-dose effectiveness (56.9%) 3
- In real-world settings, approximately 70% of people complete the two-dose series within six months, and 80% within 12 months of the initial dose 4
Recommendations for Extended Intervals
If you've waited 2 years since your first Shingrix dose:
- Get the second dose as soon as possible
- You do not need to restart the series
- The second dose will still provide additional protection beyond what was achieved with the first dose alone
Special Considerations
- For immunocompromised individuals, completing the series is particularly important, as they are at higher risk for herpes zoster and its complications 1
- The vaccine has shown effectiveness even in patients with autoimmune conditions or immunosuppressive conditions 3, 5
Potential Pitfalls to Avoid
- Don't restart the series: There is no recommendation to restart the Shingrix series regardless of the time elapsed since the first dose
- Don't substitute with Zostavax: Shingrix is the preferred vaccine with significantly higher efficacy across all age groups 1
- Don't delay further: While the 2-year interval is not ideal, further delay may leave you with suboptimal protection against herpes zoster
In summary, while the optimal timing for the second dose of Shingrix is 2-6 months after the first dose, completing the series even after a 2-year interval is better than not receiving the second dose at all.