Shingles and Its Prevention: Understanding the Virus and the Vaccines
Introduction
Shingles, also called herpes zoster, is a painful skin condition that happens when the virus that causes chickenpox becomes active again in the body², ⁵. Both chickenpox and shingles are caused by the same virus called the varicella-zoster virus (VZV)², ⁵. When someone gets chickenpox, usually as a child, their body fights off the virus, and they recover. However, the virus doesn’t completely go away. Instead, it hides in the nerve cells and stays there quietly for many years.
Later in life, especially as people get older and their immune system becomes weaker, the virus can “wake up” and cause shingles⁵. This reactivation of the virus leads to a painful rash with blisters. The rash usually appears on one side of the body and follows a line or belt-like pattern. It often starts on the back and wraps around the chest or stomach. This strip of rash is one of the reasons why the illness is called “shingles” ³, ⁵.
One of the main symptoms of shingles is pain, and for many people, it can be very severe³, ⁵. Some describe it as burning, stabbing, or throbbing pain that lasts for days or even weeks. The rash and blisters usually go away in about two to four weeks, but for some people, the pain can last much longer, even after the rash is gone³, ⁵. This lasting pain is called postherpetic neuralgia and can be very hard to live with. Other symptoms include eye complications, such as vision loss, if the nerves of the eyes are affected by the virus³.
Although shingles itself cannot be spread from one person to another, the virus in the blisters can infect someone who has never had chickenpox or the chickenpox vaccine, causing them to develop chickenpox (not shingles)³, ⁵. That’s why it’s important for people with shingles to keep the rash covered and practice good hygiene.
Vaccines play an important role in preventing shingles³,⁵. People who get the chickenpox vaccine when they are young are less likely to get shingles later in life. For older adults, especially those over 50, there is a shingles vaccine called Shingrix that helps protect against getting the disease or makes the symptoms less severe. Getting vaccinated is one of the best ways to stay healthy and avoid the pain that shingles can bring⁵.
Understanding the Link Between Chickenpox and Shingles
In 1892, a doctor named Von Bókay was the first to suggest that shingles and chickenpox might be connected. He noticed that the skin rashes from both diseases looked very similar. From his observations, he guessed that they were caused by the same virus². This idea was new at the time, and people didn’t know much about how viruses worked². In the 1920s, other scientists also began to study this idea. They did research and experiments to see if chickenpox and shingles were caused by the same thing². Some of their work supported the theory, but there were still doubts because the evidence wasn’t clear enough.
In 1965, a British doctor named R.E. Hope-Simpson made an important discovery after studying patients for 16 years². He came up with the idea that shingles happen when the chickenpox virus becomes active again later in life. He explained that after a person gets chickenpox, the virus stays hidden in the body. When someone gets older or their immune system gets weaker, the virus can “wake up” and cause shingles². This was a breakthrough that helped doctors understand that shingles and chickenpox are closely related.
Zostavax: The First Shingles Vaccine
The first vaccine made to help prevent shingles was called Zostavax². In the 1990s, scientists and doctors created this vaccine to protect older adults from getting shingles. As people age, their immune system becomes weaker, which makes it easier for the virus that causes shingles to become active again. Zostavax was designed to “boost” the immune system and help the body stay strong enough to stop the virus from reactivating².
Zostavax is known as a live vaccine³. This means it contains a weakened version of the virus. The virus is not strong enough to cause illness, but it helps the body learn how to fight it³. Once the vaccine is given, the body creates antibodies—special proteins that recognize and fight the real virus if it shows up later³.
In 2005, researchers tested Zostavax in a large study with more than 38,000 people aged 60 and older². The study showed that people who got the vaccine were about 50% less likely to get shingles than people who didn’t. Even if they did get shingles, the illness was milder, less painful, and they got better faster². The vaccine also helped prevent long-lasting nerve pain, a common problem caused by shingles, in about 65% of people². Therefore in 2006, Zostavax was approved as a vaccine for shingles⁴. It was used for several years but has since been discontinued in Canada and replaced by the newer Shingrix vaccine.
Zostavax was shown to be safe, with very few serious side effects. At first, doctors recommended it for people 60 years and older, but later studies showed it worked well in people between 50 and 59 years old too² unless they are pregnant, have a weak immune system, or are allergic to certain ingredients².
Shingrix: A New and Improved Vaccine
While Zostavax helped many people avoid shingles, its effectiveness wasn’t the same for everyone. For adults between the ages of 50 and 59, Zostavax was about 70% effective. But for those aged 70 and older, its effectiveness dropped to around 38%⁴. As people age, their immune systems get weaker, so they need stronger protection. Because of this, a newer and more effective vaccine was developed.
In October 2017, a new shingles vaccine called Shingrix was approved by the FDA, and it quickly became the preferred vaccine for preventing shingles⁴. One of the biggest differences between Shingrix and Zostavax is that Shingrix is not a live vaccine. Instead, it is an inactivated vaccine, which means it only contains a small, harmless piece of the virus³,⁴. This is helpful because it makes the vaccine safe for people with weak immune systems, who may not be able to get live vaccines³. Shingrix is currently the only shingles vaccine available in Canada³,⁴.
Shingrix also includes a special ingredient called an adjuvant, which boosts the body’s immune response, especially in older adults⁴. It is given in two doses, with the second dose typically 2 to 6 months after the first. Although Shingrix may cause mild side effects like soreness or swelling at the injection site, its benefits are clear³. It is much more effective at protecting adults over 70, which is the age group most at risk for shingles.
Because of its strong protection, health experts now recommend getting Shingrix, even if you’ve already had the Zostavax shot³. This helps ensure better long-term protection against shingles and its painful complications. In 2025, the National Advisory Committee on Immunization (NACI) also recommended Shingrix for adults 18 years and older who are immunocompromised¹.
Shingles Vaccination Program in Ontario
Since mid-October 2020, Ontario has updated its free shingles vaccination program. The province has switched from using the Zostavax II vaccine to the newer and more effective Shingrix vaccine⁴,⁵. While the vaccine itself has changed, the rules for who can get it for free have stayed the same⁴,⁵. Shingrix is given in two doses, meaning you will need to get two shots a few months apart for full protection⁴,⁵.
The program is available to seniors between the ages of 65 and 70 (from their 65th birthday up to the day before their 71st birthday). If you are in this age group and have not already received Zostavax II through Ontario’s free program, you can now get Shingrix at no cost⁴,⁵. This change is meant to help protect older adults from shingles, especially since Shingrix works better for people over 70⁴,⁵.
If you are over 70 or not in the eligible age range, you can still talk to your family doctor or nurse practitioner. They can help you decide if getting the shingles vaccine is a good choice for your health⁴,⁵. If you’re not eligible for the free program, you might still be able to buy the vaccine privately⁴,⁵.
Conclusion
Shingles is a serious and painful condition that affects many older adults. It is caused by the same virus that leads to chickenpox—called the varicella-zoster virus², ⁵. Even after someone recovers from chickenpox, the virus stays in the body and can become active again later in life, especially when the immune system gets weaker⁵. Luckily, scientists have worked hard to create vaccines to help protect people from shingles and its complications.
The first vaccine, Zostavax, gave important protection but was not very effective for people over 70 years old², ⁴. It has now been discontinued in Canada and replaced by Shingrix, a newer vaccine that is stronger, safer for people with weak immune systems, and provides better long-term protection³, ⁴. In Ontario, the government now offers Shingrix for free to seniors between the ages of 65 and 70, which helps more people stay healthy and avoid the pain caused by shingles⁴, ⁵.
Understanding the importance of shingles vaccines and knowing when and how to get them can make a big difference in protecting the health and well-being of older adults. Vaccination is one of the best ways to prevent this painful illness and improve quality of life as we age.
Reference
Canada, Public Health Agency of. (2025, May 14). Summary: Updated recommendations on herpes zoster vaccination for adults who are immunocompromised [Guidance]. https://www.canada.ca/en/public-health/services/publications/vaccines-immunization/national-advisory-committee-immunization-summary-updated-recommendations-herpes-zoster-vaccination-adults-immunocompromised.html
Galetta, K. M., & Gilden, D. (2015). Zeroing in on zoster: A tale of many disorders produced by one virus. Journal of the Neurological Sciences, 358(1), 38–45. https://doi.org/10.1016/j.jns.2015.10.004
Labos, C. (2018). Shingrix vs. Zostavax: How do various shingles vaccines stack up? Office for Science and Society. https://www.mcgill.ca/oss/article/health-and-nutrition/shingrix-vs-zostavax-how-do-various-shingles-vaccines-stack
Maltz, F., & Fidler, B. (2019). Shingrix: A new herpes zoster vaccine. Pharmacy and Therapeutics, 44(7), 406–433.
Ministry of Health. (2024). Ontario publicly funded shingles (herpes zoster) immunization program: Shingrix® vaccine information for patients. https://www.ontario.ca/files/2024-03/moh-shingrix-patient-fact-sheet-en-2024-02-15_0.pdf
Toronto, City of. (2023, April 13). Shingles (herpes zoster) vaccine. https://www.toronto.ca/community-people/health-wellness-care/diseases-medications-vaccines/shingles-herpes-zoster-vaccine/
By Farhana Bhanji