Wellington, January 3,2024
New research has found that getting vaccinated against shingles could significantly reduce the risk of suffering a stroke or heart attack from the virus.
But more information is needed to assess the vaccine’s effectiveness with regard to indigenous people in New Zealand.
Shingles, the painful skin rash caused by the same virus that is behind chicken pox, increases the risk of having a stroke or heart attack among senior citizens.
People who get chicken pox develop shingles later in life if the virus becomes active again, the study says.
“Shingles results in a painful skin rash, but we also know there’s an increased risk of having a stroke or heart attack in the first month after the virus is reactivated,” says James Mbinta, the study’s lead author and doctoral candidate in the School of Health at the Victoria University of Wellington.
The risk of stroke is two to three times higher if the virus recurs in the ophthalmic nerve, “a sensory nerve in the face,” the study notes.
As part of the study, researchers compared post-vaccine hospitalisation cases during the high-risk period of the initial 42 days with the number of those hospitalised between 72 and 162 days after vaccination (also known as the ‘control period’).
“We found twice as many people (761) were hospitalised in the control period than in the first month following vaccination (321).
“These results suggest the vaccine may reduce the risk of stroke and heart attack by as much as 50 percent in the first 42 days,” Mbinta says.
This finding is based on analysis of data from 278,375 adults in New Zealand who were vaccinated between April 2018 and July 2021, and aged 70 and above.
Vaccination reduces the chances of being hospitalised as a result of the virus, notes Prof Colin Simpson, associate dean at Victoria University’s Faculty of Health.
“The results are consistent with research in Australia that found a reduced risk of stroke after vaccination among adults aged 70 to 79,” Prof Simpson says.
The vaccine also reduces the risk of being hospitalised with “post-herpetic neuralgia, a complication of the shingles virus that can cause debilitating pain,” the research finds.
It adds about one in three people will get shingles during their lifetime, with those aged 85 and above at highest risk.
The research finds nearly a third of the population are at risk of developing shingles during their lifetime.
In New Zealand, prior to the vaccination programme, the incidence of shingles was 4.9 percent per 1000 patients. Adults aged between 80 and 90 years recorded 12.8 percent per 1,000 patients.
The debilitating pain caused by post-herpetic neuralgia (PHN) usually persists for 90 days or more and results in eye complications such as keratitis, corneal ulceration, iridocyclitis and blindness.
But the study notes that “although there are numerous therapeutic options, the management of Herpes Zoster (HZ) [or shingles] and associated complications is often suboptimal.”
Only half the patients experience “partial symptom relief,” researchers note. They prioritise “prevention through vaccination” as a way of mitigating the effects of shingles on health and quality of life, and “increasing economic burden,” especially among older adults.
The vaccination boosts immunity and prevents the reactivation of the chicken pox virus that causes shingles.
However, researchers acknowledge that, while the vaccine is licensed and marketed in many countries for adults over 50 years, and clinical trials have demonstrated its safety and efficacy, further evidence is needed from “national real-world observational studies” to buttress those findings.
Its use in New Zealand has been approved since 1 April 2018 [for adults aged over 50] and is available free of cost for 65-year-olds.
“To our knowledge, since the vaccine was introduced, no HZ vaccine effectiveness analysis has been carried out in New Zealand,” the researchers point out.
They also say there is not enough information on how the vaccine performs for sections of the population such as “Maori, the indigenous people (Tangata whenua) of New Zealand,” and needs to be studied further for the benefit of policymakers, health practitioners and the public.
Venu Menon is an Indian Newslink reporter based in Wellington