From the Research
Yes, the Shingrix vaccine is still effective if the second dose is administered 7 months after the first dose, even though the recommended interval is 2-6 months. The Centers for Disease Control and Prevention (CDC) advises that if more time has elapsed since the first dose, you should get the second dose as soon as possible, but you don't need to restart the vaccine series. Shingrix is a two-dose vaccine series designed to protect against herpes zoster (shingles) by boosting immunity against the varicella-zoster virus. The first dose primes the immune system, while the second dose strengthens and extends the protective response. While following the recommended schedule is ideal for optimal protection, receiving the second dose late is significantly better than not completing the series at all. After receiving the delayed second dose, you should develop the full protective immunity against shingles that the complete vaccine series provides.
Key Points
- The immune system still recognizes and responds to the second dose even with this delay 1.
- Receiving the second dose late is significantly better than not completing the series at all.
- The vaccine effectiveness was not significantly lower for beneficiaries aged >80 years, for second doses received at ≥180 days, or for individuals with autoimmune conditions 1.
- Two-dose vaccine effectiveness against postherpetic neuralgia was 76.0% (95% CI, 68.4-81.8) 1.
Evidence
The study by 1 found that the vaccine effectiveness of Shingrix was 70.1% (95% CI, 68.6-71.5) for 2 doses, and 56.9% (95% CI, 55.0-58.8) for 1 dose. Another study by 2 also found that the recombinant zoster vaccine (RZV) was probably effective in preventing shingles disease for at least three years. However, the most recent and highest quality study by 3 found that the effectiveness of Shingrix in patients with inflammatory arthritis on immunomodulatory treatment was 50%.
Recommendation
The Shingrix vaccine should still be administered as soon as possible if the second dose is delayed, without restarting the vaccine series. This is because the immune system still recognizes and responds to the second dose even with this delay, and receiving the second dose late is significantly better than not completing the series at all. It is also important to note that the vaccine effectiveness was not significantly lower for beneficiaries aged >80 years, for second doses received at ≥180 days, or for individuals with autoimmune conditions.