Understanding Shingles: Causes and Impact
What is Shingles?
Shingles is a viral infection characterized by painful skin rashes and blisters. It is caused by the varicella-zoster virus, the same virus responsible for chickenpox. Research indicates that approximately one in four individuals will experience shingles during their lifetime, with a higher incidence observed in people over the age of 50.
Prevention of Shingles
The primary method for preventing shingles is through the administration of live-attenuated vaccines, which introduce a weakened form of the virus into the body. However, the effectiveness of these vaccines tends to decline after the age of 70. Additionally, there are specific circumstances where live-attenuated vaccines are not recommended, particularly for individuals undergoing immunosuppressive therapy.
Advancements in Vaccine Technology
Recombinant vaccines present an alternative approach, utilizing recombinant DNA technology to introduce specific viral protein subunits instead of the live virus. This innovation aims to address some limitations associated with live-attenuated vaccines.
Recent Research Findings
New Recombinant Vaccine: Shingrix
In the previous year, a new recombinant vaccine named Shingrix received regulatory approval and is now available in Canada. A systematic review conducted by researchers at St. Michael’s Hospital in Toronto was recently published in the BMJ, comparing the effectiveness of the live-attenuated shingles vaccine with that of the recombinant subunit vaccine.
Study Overview
The review incorporated data from 27 studies involving over 2 million patients aged 50 and older. The findings revealed that the recombinant vaccine was 85% more effective in preventing shingles compared to the live-attenuated vaccine. However, it was also associated with a 30% higher likelihood of experiencing adverse effects at the injection site. Notably, no significant differences in the occurrence of severe adverse events were identified between the two vaccines.
Conclusion and Recommendations
The authors of the study concluded that despite the increased risk of side effects, the recombinant subunit vaccine is superior to the live-attenuated vaccine in shingles prevention. They advocate for further studies to evaluate the cost-effectiveness of both vaccination options, particularly given that the recombinant vaccine requires two doses, while the live-attenuated vaccine only necessitates one.
References
Tricco AC et al. Efficacy, effectiveness, and safety of herpes zoster vaccines in adults aged 50 and older: systematic review and network meta-analysis. BMJ. 2018 Oct 25;363:k4029. doi: 10.1136/bmj.k4029.
St. Michael’s Hospital. Systematic review of clinical studies suggests newer shingles vaccine far more effective. https://www.eurekalert.org/pub_releases/2018-10/smh-sro102518.php. Published October 25, 2018.
GSK Canada. SHINGRIX approved in Canada as the first non-live adjuvanted vaccine to help protect against shingles. http://ca.gsk.com/en-ca/media/press-releases/2017/shingrix-approved-in-canada-as-the-first-non-live-adjuvanted-vaccine-to-help-protect-against-shingles/. Published October 13, 2017.