tom asked
I finally received my 2nd dose of the Shingrix well after the two to six-month timeline. It has been 8 months to be exact due to the short supply. Will that be ok or will it not be effective?
At a glance
- If you are late for your second Shingrix dose (i.e. it has been more than 6 months from your first dose), it is recommended to administer it as soon as possible and do not restart the vaccine series. There likely will not be any appreciable loss in its ability to protect you from shingles.
Answer
We have been hearing this all too often, unfortunately! You aren't alone in having difficulty finding a pharmacy that has the Shingrix vaccine available for your second dose when it comes due (which is 2 to 6 months after your first dose).[1]
This is due to the well-documented shortage of Shingrix, which the CDC (Centers for Disease Control) predicts will continue throughout 2019.[2]
Late For The Second Dose
The recommended dosing schedule for Shingrix is as a two-shot series:
- One dose initially followed by a second dose 2 to 6 months later.[1]
The question of what to do if it has been more than 6 months since your first dose comes up often.
First off, if you have had trouble finding a location that has the vaccine in stock and it has been more than 6 months since your first dose, you do not have the start the vaccine series over again.
The two most authoritative resources on the matter, the CDC and Immunization Action Coalition, recommend the following:
- Continue to look for the second dose of the vaccine (using the online vaccine finder tool can help) and get it as soon as possible.
- You should not restart the vaccine series.
- Do not substitute the other herpes vaccine (Zostavax) for your second dose.
The following excerpt is from the 'Ask The Experts' section on Immunize.org:[3]
If more than 6 months have elapsed since the first dose of RZV [Shingrix], administer the second dose when possible. Do not restart the vaccine series, and do not substitute ZVL [Zostavax] for the second dose of RZV [Shingrix]. If you are out of RZV [Shingrix] and a patient needs a second dose, the Vaccine Finder may be helpful for patients to locate other providers that have RZV [Shingrix] in stock.
Does The Vaccine Lose Effectiveness?
It isn't definitively known if the Shingrix vaccine is less effective if you are late in getting your second dose.
We do know that the second dose of Shingrix is necessary to boost your immune system to the point where it can be most effective in preventing an outbreak of shingles, so you certainly want to keep looking for the second dose and get it as soon as possible.[4]
Most data indicates that there will be minimal if any, loss in efficacy as long as you get your second dose as soon as possible if it has been over 6 months.
However, one study suggests that if you still haven't received your second dose 12 months after your first dose, it may not be as effective, but again, this isn't known for sure.[5]
Simply follow the directions per the CDC and keep looking for the second dose to be administered as soon as you can so you can have the most confidence that it will be fully effective.
References
- ^ Shingrix Prescribing Information. PubMed
- ^ CDC Vaccine Shortages Centers for Disease Control
- ^ Immunization Action Coalition: Ask The Experts
- ^ Efficacy of the Herpes Zoster Subunit Vaccine in Adults 70 Years of Age or Older. New England Journal of Medicine
- ^ Immunogenicity, reactogenicity and safety of 2 doses of an adjuvanted herpes zoster subunit vaccine administered 2, 6 or 12 months apart in older adults: Results of a phase III, randomized, open-label, multicenter study. PubMed
