Herpes zoster (shingles) vaccine

• herpes zoster (HZ) is an often painful neurocutaneous syndrome resulting from reactivation of varicella-zoster virus (VZV) that has remained latent in sensory ganglia after primary VZV infection (varicella, chickenpox)
  • frequency and severity of HZ and its most common debilitating complication, postherpetic neuralgia (PHN), increase with age
    • due to lengthening lifespans, there are increasing concerns about quality of life for older adults, a growing segment of the population, especially in high-income countries
      • in the United States, the annual incidence of herpes zoster increased from 3.10 episodes per 1000 in older adults in 2000 to 5.22 in 2007
        
        
  • age-related increase in disease correlates closely with the decline in VZV-specific T cell mediated immunity (VZV-CMI) that accompanies aging
    • HZ frequently occurs in circumstances when VZV-CMI is depressed while levels of VZV antibody are maintained by intravenous gamma-globulin, such as those following hematopoietic stem cell transplantation
      • unlikely that antibodies to VZV play a role in this relationship, because they do not decline with aging
        
        
• herpes zoster (shingles) vaccine
  • herpes zoster and VZV vaccines (used for children in the USA) both contain the same attenuated VZV strain (ie both are 'live' vaccines), but the herpes zoster vaccine has greater than 14-fold more plaque-forming units (PFUs) per dose. Therefore the two vaccines are not interchangeable (1,2)
    • vaccine is contraindicated in patients with immunosuppressive conditions. These individuals should receive other types of vaccines such as heat-inactivated or replication-defective VZV

Key points about the changes to the programme in the England from September 1st 2023 (3)

Change of vaccine

• Shingrix(R) will replace Zostavax(R) for the whole shingles programme
• Shingrix(R) will require a 2-dose schedule for all cohorts. The dosing interval will differ for immunocompromised and immunocompetent patients
• Shingrix(R) should be offered to all people reaching eligible age on or after 1 September 2023. Those cohorts previously eligible for Zostavax(R) who are under 80 years of age, should continue to be offered Zostavax(R) until central stocks deplete (via ImmForm), after which they should be offered Shingrix(R)
• individuals who have received Zostavax(R) previously should not be revaccinated with Shingrix(R)
• Shingrix(R) can be administered alongside other vaccines. Please refer to the Shingles Green Book chapter for more information
• in 2018, it was agreed that patients could be immunised with shingles vaccine at any point in the year as soon as they reach eligible age. Shingles vaccination should continue to be offered year-round

Changes to eligibility

Immunocompromised cohort

• since September 2021, Shingrix(R) has been available to immunocompromised individuals aged 70 to 79 years, who are contraindicated to receive Zostavax(R), as part of the NHS shingles vaccination programme
• the forthcoming change from 1 September 2023 will expand the eligibility to all immunocompromised individuals aged 50 years and over (with no upper age limit)
• immunocompromised individuals who have already received 2 doses of Shingrix(R) do not need re-vaccination
• immunocompromised individuals represent the highest priority for vaccination given their risk of severe disease, and therefore the programme aims to catch up all immunocompromised individuals aged 50 years and over in the first year of the programme implementation.

The second dose should be given 8 weeks to 6 months after the first dose for this cohort, in line with the Summary of Product Characteristics (SPC)

Immunocompetent cohort

• the eligible age for immunocompetent individuals will change from 70 to 60 years of age for the routine cohort, in a phased implementation over a 10 year period
• the routine offer will move from 70 to 60 years of age in 2 stages over a 10 year period as follows:
• during stage 1 (1 September 2023 to 31 August 2028)
  • Shingrix(R) will be offered to those turning 70 and 65 years on or after 1 September 2023.
  • Zostavax(R) will be offered to persons aged between 70 to 79 that were eligible for the vaccination programme before 1 September 2023. Once all stocks of Zostavax(R) are exhausted, these individuals can be offered Shingrix(R) if they have not previously been given a shingles vaccine
• during stage 2 (1 September 2028 to 31 August 2033)
  • Shingrix(R) will be offered to those turning 65 and 60 years of age.
  • from 1 September 2033 and thereafter, Shingrix(R) will be offered routinely at age 60 years
  • those who have been previously eligible ( in stages 1 and 2) will remain eligible until their 80th birthday

Comparing single dose vaccine versus double dose vaccine (4)

• study (n=1,996,885 patients aged ≥50 years) found two doses of recombinant zoster vaccine were highly effective, with effectiveness generally maintained over 4 years
  • however, one dose effectiveness waned substantially after 1 year, underlining the need for two doses

Reference:

• Gagliardi AM, Gomes Silva BN, Torloni MR, et al; Vaccines for preventing herpes zoster in older adults. Cochrane Database Syst Rev. 2012 Oct 17;10:CD008858. doi: 10.1002/14651858.CD008858.pub2.
• Levin MJ et al.Varicella-zoster virus-specific immune responses in elderly recipients of a herpes zoster vaccine. J Infect Dis. 2008 Mar 15;197(6):825-35
• NHS England (July 4th 2023). Introduction of Shingrix (R) vaccine for the whole programme and expansion of eligible cohorts letter
• Ousseny Zerbo, Joan Bartlett, Bruce Fireman, et al. Effectiveness of Recombinant Zoster Vaccine Against Herpes Zoster in a Real-World Setting. Ann Intern Med.[Epub 9 January 2024]