US Shingles Update: Cases Up, but Vaccination Rates Increasing
Decades after the introduction of the chickenpox vaccine and 14 years after the first shingles vaccine was approved in the United States, it’s time to take stock of where the country is in respect to shingles infections
Decades after the introduction of the chickenpox vaccine and 14 years after the first shingles vaccine was approved in the United States, it’s time to take stock of where the country is in respect to shingles infections. The bad news is infection rates are up; the good news is there is an effective shingles vaccine that holds promise for the future.
First, some background on the subject from Jeffrey I. Cohen, MD, chief, Laboratory of Infectious Diseases at the National Institutes of Health (NIH). Shingles (herpes zoster, or HZ) is caused by a reactivation of the varicella zoster virus (VZV) that causes chickenpox. “During chickenpox, the virus spreads in the blood and infects the nerves. Those nerves are seeded with virus, meaning the virus is there and stays in those nerve cells for the life of the person,” explained Cohen. “It can reactivate at a later time from the nerves, causing shingles.”
This is the scenario that plays out for approximately 1 in 3 Americans, accounting for an estimated 1 million cases of shingles annually. According to the CDC, although the shingles infection rate among older adults has plateaued in recent years, the rates among younger and middle aged adults have been gradually increasing over a long period of time.1
One study reported on by JAMA Dermatology revealed that although chickenpox and shingles vaccines may be reducing HZ-related emergency room visits for children and patients over the age of 60, the numbers are up for patients between 20 and 60 years of age.2
The reasons for the overall rise in rates are unclear. Prior to the introduction of the varicella vaccine in 1996, there was speculation in the medical community that the number of shingles cases would increase based on the theory that exposure to chickenpox boosts an individual’s immunity to VZV and reduces the risk that it will reactivate as shingles. That is, as more children received the varicella vaccine and the number of chickenpox cases declined, shingles cases in adults would rise.2
However, 2 subsequent CDC studies found that the shingles rates began increasing in the US before the chickenpox vaccine was introduced and did not increase faster afterwards. Additionally, there have been similar increases in shingles rates in countries that do not have routine chickenpox vaccination programs.2
One important question remains unanswered: Will shingles eventually just disappear once generations of people have been vaccinated against chickenpox? “Epidemiologists are predicting that it will go away, or at least become very rare in the US,” said neurologist Anne Louise Oaklander, MD, PhD, and director of the Nerve Unit at Massachusetts General Hospital. “We hope that with the new vaccination this will become of historical interest only. But it’s very much with us right now.”
Recent data from the CDC revealed that the shingles vaccination rate is increasing in the US, currently almost 35% and surpassing the agency’s Healthy People 2020 target of 30%.
Shingrix is now the only shingles vaccine since Merck announced earlier this year that it was removing Zostavax from the US. market. Approved by the FDA in 2017 for use in people 50 years and older, Shingrix is administered in a 2-dose series and has proven to be over 90% effective at preventing shingles in clinical trials across all age groups tested.
References
1. CDC. Shingles (Herpes Zoster). Page last reviewed: August 14, 2019. Accessed September 3, 2020. https://www.cdc.gov/shingles/hcp/clinical-overview.html.
2. What Are Trends in Emergency Department Utilization, Costs for Shingles? News Release. JAMA Dermatology; June 21, 2017. Accessed September 3, 2020. https://media.jamanetwork.com/news-item/trends-emergency-department-utilization-costs-shingles/.
