Vaccines for preventing herpes zoster in older adults.

BACKGROUND: Herpes zoster, also known as 'shingles', is a neurocutaneous disease characterised by the reactivation of the latent varicella zoster virus (VZV), the virus that causes chickenpox when immunity to VZV declines. It is an extremely painful condition that can last many weeks or months and it can significantly compromise the quality of life of affected individuals. The natural process of aging is associated with a reduction in cellular immunity and this predisposes older people to herpes zoster. Vaccination with an attenuated form of VZV activates specific T cell production avoiding viral reactivation. The Food and Drug Administration has approved a herpes zoster vaccine with an attenuated active virus for clinical use among older adults, which has been tested in large populations. A new adjuvanted recombinant VZV subunit zoster vaccine has also been tested. It consists of recombinant VZV glycoprotein E and a liposome-based AS01B adjuvant system. This new vaccine is not yet available for clinical use. OBJECTIVES: To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults. SEARCH METHODS: For this 2015 update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 9), MEDLINE (1948 to the 3rd week of October 2015), EMBASE (2010 to October 2015), CINAHL (1981 to October 2015) and LILACS (1982 to October 2015). SELECTION CRITERIA: Randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine with placebo or no vaccine, to prevent herpes zoster in older adults (mean age > 60 years). DATA COLLECTION AND ANALYSIS: Two review authors independently collected and analysed data using a data extraction form. They also performed 'Risk of bias' assessment. MAIN RESULTS: We identified 13 studies involving 69,916 participants. The largest study included 38,546 participants. All studies were conducted in high-income countries and included only healthy Caucasian individuals ≥ 60 years of age without immunosuppressive comorbidities. Ten studies used live attenuated varicella zoster virus (VZV) vaccines. Three studies tested a new type of vaccine not yet available for clinical use. We judged five of the included studies to be at low risk of bias.The incidence of herpes zoster, at up to three years of follow-up, was lower in participants who received the vaccine than in those who received a placebo: risk ratio (RR) 0.49; 95% confidence interval (CI) 0.43 to 0.56, risk difference (RD) 2%, number needed to treat to benefit (NNTB) 50; GRADE: moderate quality evidence. The vaccinated group had a higher incidence of mild to moderate intensity adverse events. These date came from one large study that included 38,546 people aged 60 years or older.A study including 8122 participants compared the new vaccine (not yet available) to the placebo; the group that received the new vaccine had a lower incidence of herpes zoster at 3.2 years of follow-up: RR 0.04, 95% CI 0.02 to 0.10, RD 3%, NNTB 33; GRADE: moderate quality evidence. The vaccinated group had a higher incidence of adverse events but most them were of mild to moderate intensity.All studies received funding from the pharmaceutical industry. AUTHORS' CONCLUSIONS: Herpes zoster vaccine is effective in preventing herpes zoster disease and this protection can last three years. In general, zoster vaccine is well tolerated; it produces few systemic adverse events and injection site adverse events of mild to moderate intensity.There are studies of a new vaccine (with a VZV glycoproteic fraction plus adjuvant), which is currently not yet available for clinical use.

Vaccines for preventing herpes zoster in older adults.

BACKGROUND: Herpes zoster or, as it is commonly called, 'shingles' is a neurocutaneous disease characterised by the reactivation of varicella zoster virus (VZV), the virus that causes chickenpox, which is latent in the dorsal spinal ganglia when immunity to VZV declines. It is an extremely painful condition which can often last for many weeks or months, impairing the patient's quality of life. The natural aging process is associated with a reduction of cellular immunity which predisposes to herpes zoster. Vaccination with an attenuated form of VZV activates specific T cell production, therefore avoiding viral reactivation. A herpes zoster vaccine with an active virus has been approved for clinical use among older adults by the Food and Drug Administration and has been tested in large populations. OBJECTIVES: To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults. SEARCH METHODS: We searched the following sources for relevant studies: CENTRAL 2012, Issue 7, MEDLINE (1948 to July week 1, 2012), EMBASE (2010 to July 2012), LILACS (1982 to July 2012) and CINAHL (1981 to July 2012). We also reviewed reference lists of identified trials and reviews for additional studies. SELECTION CRITERIA: Randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine with placebo or no vaccine, to prevent herpes zoster in older adults (mean age > 60 years). DATA COLLECTION AND ANALYSIS: Two review authors independently collected and analysed data using a data extraction form. They also carried out an assessment of risk of bias. MAIN RESULTS: We identified eight RCTs with a total of 52,269 participants. Three studies were classified at low risk of bias. The main outcomes on effectiveness and safety were extracted from one clinical trial with a low risk of bias. Four studies compared zoster vaccine versus placebo; one study compared high-potency zoster vaccine versus low-potency zoster vaccine; one study compared refrigerated zoster vaccine versus frozen zoster vaccine; one study compared live zoster vaccine versus inactivated zoster vaccine and one study compared zoster vaccine versus pneumococcal polysaccharide vaccine (pneumo 23).Confirmed cases of herpes zoster were less frequent in patients who received the vaccine than in those who received a placebo: risk ratio (RR) 0.49 (95% confidence interval (CI) 0.43 to 0.56), with a risk difference (RD) of 2%, and number needed to treat to benefit (NNTB) of 50. Analyses according to age groups indicated a greater benefit in participants aged 60 to 69 years, RR 0.36 (95% CI 0.30 to 0.45) and in participants aged 70 years and over, RR 0.63 (95% CI 0.53 to 0.75). Vaccine-related systemic adverse effects were more frequent in the vaccinated group (RR 1.29, 95% CI 1.05 to 1.57, number needed to treat to harm (NNTH) = 100). The pooled data risk ratio for adverse effects for participants with one or more inoculation site adverse effect was RR 4.51 (95% CI 2.35 to 8.68), and the NNTH was 2.8 (95% CI 2.3 to 3.4). Side effects were more frequent in younger (60 to 69 years) than in older (70 years and over) participants. AUTHORS' CONCLUSIONS: Herpes zoster vaccine is effective in preventing herpes zoster disease. Although vaccine benefits are larger in the younger age group (60 to 69 years), this is also the age group with more adverse events. In general, zoster vaccine is well tolerated; it produces few systemic adverse events and injection site adverse effects of mild to moderate intensity.