Zostavax was a vaccine developed to prevent shingles, a painful condition caused by the reactivation of the chickenpox virus. Introduced as a single-dose injection, it aimed to reduce the incidence and severity of shingles, particularly in older adults. While no longer available in the United States, its development marked a step in preventing this viral disease.
Understanding Zostavax and Shingles
Zostavax was designed to prevent shingles, a painful rash with blisters caused by the varicella-zoster virus (VZV). This virus, also responsible for chickenpox, remains dormant in nerve cells after an initial infection.
The virus can reactivate later in life, particularly as the immune system naturally weakens with age. This reactivation leads to the characteristic shingles rash, which typically forms a stripe of blisters on one side of the body. Zostavax aimed to bolster the body’s immune response against this latent virus, helping to prevent its reactivation and the development of shingles.
How Zostavax Works and Who It Was For
Zostavax (NDC 0006-4963-00) was a live, attenuated (weakened) virus vaccine. It contained a modified VZV form that prompted the immune system to produce a stronger defense, helping keep the dormant VZV in check and reducing shingles risk.
The vaccine was administered as a single 0.65-mL subcutaneous injection, typically under the skin. Initially, Zostavax was recommended for adults aged 60 and older, though it received FDA approval for individuals 50 and older. However, it was not suitable for those with compromised immune systems due to disease or certain therapies, or those who were pregnant.
Efficacy and Side Effects
Zostavax demonstrated effectiveness in preventing shingles and reducing the severity of the disease and its complications. Clinical studies showed it reduced the incidence of shingles by approximately 51% over a mean follow-up of three years. For adults aged 50 to 59, the vaccine significantly lowered the risk of developing shingles by nearly 70%. It also helped prevent postherpetic neuralgia (PHN), a long-lasting nerve pain that can occur after shingles, showing an overall 61% lower burden of disease due to PHN.
The protection provided by Zostavax was observed to wane over time. While it was 67% effective in the first year, its efficacy decreased to 50% by the second year, 27% by the eighth year, and 15% after ten years. Common side effects were generally mild to moderate and included injection site reactions such as redness, pain, swelling, warmth, bruising, or itching. Other reported side effects included headache, muscle pain, and occasionally diarrhea or skin rash.
Current Status and Alternatives
Zostavax is no longer available for use in the United States, with its discontinuation occurring on November 18, 2020. This change largely stemmed from the introduction of a newer, more effective vaccine. While Zostavax provided a measure of protection, a recombinant subunit vaccine, Shingrix, became available and offered higher and more sustained immunity.
Shingrix (NDC 58160-823-11) is now the preferred and currently recommended vaccine for shingles by health organizations. Unlike Zostavax, Shingrix is a non-live vaccine and is administered as a two-dose series. The doses are typically given two to six months apart for immunocompetent individuals, or one to two months apart for those who are immunocompromised. Anyone considering shingles vaccination should discuss their options with a healthcare provider to determine the most appropriate course of action.