Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a common, serious, painful complication of herpes zoster. Corticosteroids have anti-inflammatory properties, and might be beneficial. This is an update of a review first published in 2008, and previously updated in 2013.

OBJECTIVES

To assess the effects (benefits and harms) of corticosteroids in preventing postherpetic neuralgia.

SEARCH METHODS

We updated the searches for randomised controlled trials (RCTs) of corticosteroids for preventing postherpetic neuralgia in the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, two other databases, and two trials registers (June 2022). We also reviewed the bibliographies of identified trials, contacted authors, and approached pharmaceutical companies to identify additional published or unpublished data.

SELECTION CRITERIA

We included all RCTs involving corticosteroids given by oral, intramuscular, or intravenous routes for people of all ages, with herpes zoster of all degrees of severity within seven days after onset, compared with no treatment or placebo, but not with other treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified potential articles, extracted data, assessed the risk of bias of each trial, and the certainty of the evidence. Disagreement was resolved by discussion among the co-authors. We followed standard Cochrane methodology.

MAIN RESULTS

We identified five trials with a total of 787 participants that met our inclusion criteria. No new studies were identified for this update. All were randomised, double-blind, placebo-controlled parallel-group studies. The evidence is very uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection in preventing postherpetic neuralgia six months after the onset of herpes (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.45 to 1.99; 2 trials, 114 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)). The three other trials that fulfilled our inclusion criteria were not included in the meta-analysis because they did not provide separate information on the number of participants with PHN at six months. Adverse events during or within two weeks after stopping treatment were reported in all five included trials. There were no observed differences in serious (RR 1.65, 95% CI 0.51 to 5.29; 5 trials, 755 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)), or non-serious adverse events (RR 1.30, 95% CI 0.90 to 1.87; 5 trials, 755 participants; low-certainty evidence (downgraded for serious risk of bias and serious imprecision)) between the corticosteroid and placebo groups. One of these trials was at high risk of bias because of incomplete outcome data, two were at unclear risk of bias, and the other was at low risk of bias. The review was first published in 2008; no new RCTs were identified for inclusion in subsequent updates in 2010, 2013, and 2023.

AUTHORS' CONCLUSIONS

Based on the current available evidence, we are uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection on preventing postherpetic neuralgia. Corticosteroids given orally or intramuscularly may result in little to no difference in the risk of adverse events in people with acute herpes zoster. Some researchers have recommended using corticosteroids to relieve the zoster-associated pain in the acute phase of the disease. If further research is designed to evaluate the efficacy of corticosteroids for herpes zoster, long-term follow-up should be included to observe their effect on the transition from acute pain to postherpetic neuralgia. Future trials should include measurements of function and quality of life, as well as updated measures of pain.

Vaccines for preventing herpes zoster in older adults

BACKGROUND

Herpes zoster, commonly known as shingles, is a neurocutaneous disease caused by the reactivation of the virus that causes varicella (chickenpox). After resolution of the varicella episode, the virus can remain latent in the sensitive dorsal ganglia of the spine. Years later, with declining immunity, the varicella zoster virus (VZV) can reactivate and cause herpes zoster, an extremely painful condition that can last many weeks or months and significantly compromise the quality of life of the affected person. The natural process of ageing is associated with a reduction in cellular immunity, and this predisposes older adults to herpes zoster. Vaccination with an attenuated form of the VZV activates specific T-cell production avoiding viral reactivation. Two types of herpes zoster vaccines are currently available. One of them is the single-dose live attenuated zoster vaccine (LZV), which contains the same live attenuated virus used in the chickenpox vaccine, but it has over 14-fold more plaque-forming units of the attenuated virus per dose. The other is the recombinant zoster vaccine (RZV) which does not contain the live attenuated virus, but rather a small fraction of the virus that cannot replicate but can boost immunogenicity. The recommended schedule for the RZV is two doses two months apart. This is an update of a Cochrane Review first published in 2010, and updated in 2012, 2016, and 2019.

OBJECTIVES

To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults.

SEARCH METHODS

For this 2022 update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2022, Issue 10), MEDLINE (1948 to October 2022), Embase (2010 to October 2022), CINAHL (1981 to October 2022), LILACS (1982 to October 2022), and three trial registries.

SELECTION CRITERIA

We included studies involving healthy older adults (mean age 60 years or older). We included randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine (any dose and potency) versus any other type of intervention (e.g. varicella vaccine, antiviral medication), placebo, or no intervention (no vaccine). Outcomes were cumulative incidence of herpes zoster, adverse events (death, serious adverse events, systemic reactions, or local reaction occurring at any time after vaccination), and dropouts.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two new studies involving 1736 participants in this update. The review now includes a total of 26 studies involving 90,259 healthy older adults with a mean age of 63.7 years. Only three studies assessed the cumulative incidence of herpes zoster in groups that received vaccines versus placebo. Most studies were conducted in high-income countries in Europe and North America and included healthy Caucasians (understood to be white participants) aged 60 years or over with no immunosuppressive comorbidities. Two studies were conducted in Japan and one study was conducted in the Republic of Korea. Sixteen studies used LZV. Ten studies tested an RZV. The overall certainty of the evidence was moderate, which indicates that the intervention probably works. Most data for the primary outcome (cumulative incidence of herpes zoster) and secondary outcomes (adverse events and dropouts) came from studies that had a low risk of bias and included a large number of participants. The cumulative incidence of herpes zoster at up to three years of follow-up was lower in participants who received the LZV (one dose subcutaneously) than in those who received placebo (risk ratio (RR) 0.49, 95% confidence interval (CI) 0.43 to 0.56; risk difference (RD) 2%; number needed to treat for an additional beneficial outcome (NNTB) 50; moderate-certainty evidence) in the largest study, which included 38,546 participants. There were no differences between the vaccinated and placebo groups for serious adverse events (RR 1.08, 95% CI 0.95 to 1.21) or deaths (RR 1.01, 95% CI 0.92 to 1.11; moderate-certainty evidence). The vaccinated group had a higher cumulative incidence of one or more adverse events (RR 1.71, 95% CI 1.38 to 2.11; RD 23%; number needed to treat for an additional harmful outcome (NNTH) 4.3) and injection site adverse events (RR 3.73, 95% CI 1.93 to 7.21; RD 28%; NNTH 3.6; moderate-certainty evidence) of mild to moderate intensity. These data came from four studies with 6980 participants aged 60 years or older. Two studies (29,311 participants for safety evaluation and 22,022 participants for efficacy evaluation) compared RZV (two doses intramuscularly, two months apart) versus placebo. Participants who received the new vaccine had a lower cumulative incidence of herpes zoster at 3.2 years follow-up (RR 0.08, 95% CI 0.03 to 0.23; RD 3%; NNTB 33; moderate-certainty evidence), probably indicating a favourable profile of the intervention. There were no differences between the vaccinated and placebo groups in cumulative incidence of serious adverse events (RR 0.97, 95% CI 0.91 to 1.03) or deaths (RR 0.94, 95% CI 0.84 to 1.04; moderate-certainty evidence). The vaccinated group had a higher cumulative incidence of adverse events, any systemic symptom (RR 2.23, 95% CI 2.12 to 2.34; RD 33%; NNTH 3.0), and any local symptom (RR 6.89, 95% CI 6.37 to 7.45; RD 67%; NNTH 1.5). Although most participants reported that their symptoms were of mild to moderate intensity, the risk of dropouts (participants not returning for the second dose, two months after the first dose) was higher in the vaccine group than in the placebo group (RR 1.25, 95% CI 1.13 to 1.39; RD 1%; NNTH 100, moderate-certainty evidence). Only one study reported funding from a non-commercial source (a university research foundation). All other included studies received funding from pharmaceutical companies. We did not conduct subgroup and sensitivity analyses AUTHORS' CONCLUSIONS: LZV (single dose) and RZV (two doses) are probably effective in preventing shingles disease for at least three years. To date, there are no data to recommend revaccination after receiving the basic schedule for each type of vaccine. Both vaccines produce systemic and injection site adverse events of mild to moderate intensity. The conclusions did not change in relation to the previous version of the systematic review.