Shingles (herpes zoster) is a painful viral infection that can develop in anyone who has had chickenpox. The virus, varicella-zoster, remains inactive in the body and can reactivate years later, causing a distinctive rash and nerve pain.
Differences Between Live and Inactivated Vaccines
Vaccines introduce a harmless version of a pathogen to the immune system, teaching it to recognize and fight off future infections. Vaccines differ primarily in whether they contain live attenuated viruses or inactivated components.
Live attenuated vaccines contain a weakened, living form of the virus. This weakened virus replicates in the body, stimulating a strong, long-lasting immune response, similar to a natural infection but without causing severe disease. Examples include the measles, mumps, and rubella (MMR) vaccine.
Inactivated vaccines do not contain live viruses. They use killed viral particles or specific parts of the virus, such as proteins or genetic material. These vaccines cannot replicate in the body, which makes them safer for individuals with compromised immune systems. However, they may require multiple doses or booster shots for robust immunity. The polio shot is an example of an inactivated vaccine.
Understanding Shingles Vaccine Types
Historically, two main shingles vaccines have been available in the United States. Zostavax was a live attenuated vaccine. This vaccine was approved in 2006 for individuals 50 years of age and older. However, Zostavax was discontinued in the U.S. in November 2020.
The currently recommended shingles vaccine is Shingrix, a recombinant (non-live) subunit vaccine. Shingrix uses a specific protein from the varicella-zoster virus to stimulate an immune response, and its non-live nature means it cannot cause the disease it is designed to prevent.
Why Vaccine Type Matters
The distinction between live and non-live vaccines has important implications for who can safely receive them. Live attenuated vaccines, like the former Zostavax, are generally not recommended for individuals with weakened immune systems due to the theoretical risk of the weakened virus causing illness in these vulnerable populations. This includes people undergoing chemotherapy, those with HIV/AIDS, or organ transplant recipients.
The development of Shingrix, a non-live recombinant vaccine, represents a significant advancement. Its non-live nature makes it suitable for a broader range of individuals, including many who are immunocompromised. This allows for greater protection against shingles across various health conditions. Shingrix has also shown higher efficacy in preventing shingles and its complications compared to Zostavax.
General Vaccination Guidance
Shingrix is recommended for healthy adults aged 50 years and older to prevent shingles and its complications. It is also recommended for adults aged 19 years and older who are or will be immunodeficient or immunosuppressed due to disease or therapy. The vaccine is administered as a two-dose series, with the second dose typically given two to six months after the first.
Completing both doses is important for achieving the full protective benefits. Common side effects are generally mild and temporary, including soreness, redness, or swelling at the injection site, as well as muscle pain, fatigue, or headache. Vaccination is considered the most effective way to protect against shingles and its potential long-term nerve pain, known as postherpetic neuralgia.