Randomized Controlled Trials as Topic

Rationale: Respiratory syncytial virus (RSV) is a highly transmissible pathogen that causes varying degrees of respiratory illness across all age groups. The safety and efficacy profiles of available RSV vaccines, a critical consideration for their integration into public health strategies and clinical practice, remain uncertain.

Objectives: To assess the benefits and harms of RSV vaccines compared to placebo, no intervention, vaccines for other respiratory infections, other RSV vaccines, or monoclonal antibodies (mAbs) across all human populations.

Search methods: We conducted a comprehensive literature search of CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and the WHO ICTRP following standard systematic review methodology from 2000 to April 2024.

Eligibility criteria: We included both randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs) involving all human populations comparing RSV vaccines with placebo, no intervention, vaccines for other respiratory infections, other RSV vaccines, or mAbs. We excluded studies focused on dose-finding schedules and immunogenicity assessment.

Outcomes: Benefits included frequency of RSV illness (both lower and upper respiratory illness) confirmed by laboratory tests (RSV-associated lower respiratory tract illness and RSV-associated acute respiratory illness); hospitalisation due to RSV disease (both lower and upper respiratory illness) confirmed by laboratory tests; mortality from illness caused by RSV (confirmed by laboratory test); all-cause mortality; and admission to an intensive care unit. Harms included serious adverse events (SAEs) related to vaccination, including neurological disorders such as Guillain-Barré syndrome.

Risk of bias: We assessed risk of bias in RCTs using Cochrane's RoB 2 tool.

Synthesis methods: We used standard Cochrane methods.

Included studies: We identified 14 RCTs: five trials (101,825 participants) on older adults; three trials (12,010 participants) on maternal vaccination and effects on infants; one trial (300 participants) on women of childbearing age; and five trials (192 participants) on infants and children. We identified no NRSIs.

Synthesis of results: RSV prefusion vaccine versus placebo in older adults These vaccines reduced RSV-associated lower respiratory tract illness with vaccine efficacy (VE) of 77% (95% confidence interval (CI) 0.70 to 0.83; risk ratio (RR) 0.23, 95% CI 0.17 to 0.30; 4 RCTs, 99,931 participants; high-certainty evidence) and RSV-associated acute respiratory illness with VE of 67% (95% CI 0.60 to 0.73; RR 0.33, 95% CI 0.27 to 0.40; 3 RCTs, 94,339 participants; high-certainty evidence). There may be little to no difference in mortality from illness caused by RSV, all-cause mortality, and SAEs related to vaccination (low-certainty evidence). RSV postfusion F protein-based vaccine versus placebo in older adults There is probably little to no difference in RSV-associated lower respiratory tract illness with VE of -0.37% (95% CI -1.96 to 0.37; RR 1.37, 95% CI 0.63 to 2.96; 1 RCT, 1894 participants; moderate-certainty evidence) and RSV-associated acute respiratory illness with VE of -0.07% (95% CI -1.15 to 0.47; RR 1.07, 95% CI 0.53 to 2.15; 1 RCT, 1894 participants; moderate-certainty evidence). There may be little to no difference in mortality from illness caused by RSV, all-cause mortality, and SAEs related to vaccination (low-certainty evidence). Maternal RSV F protein-based vaccine versus placebo in infants These vaccines reduced medically attended RSV-associated lower respiratory tract illness with VE of 54% (95% CI 0.28 to 0.71; RR 0.46, 95% CI 0.29 to 0.72; 3 RCTs, 12,010 participants; high-certainty evidence), medically attended RSV-associated severe lower respiratory tract illness with VE of 74% (95% CI 0.44 to 0.88; RR 0.26, 95% CI 0.12 to 0.56; 3 RCTs, 12,010 participants; high-certainty evidence), and hospitalisation due to RSV disease with VE of 54% (95% CI 0.27 to 0.71; RR 0.46, 95% CI 0.29 to 0.73; 2 RCTs, 11,502 participants; high-certainty evidence) in infants. There may be little to no difference in mortality from illness caused by RSV, all-cause mortality, and SAEs related to vaccination in mothers and infants (low-certainty evidence). Live-attenuated RSV vaccines versus placebo in infants and children The evidence is very uncertain regarding all-cause medically attended acute respiratory illness (MAARI) with VE of 26% (95% CI -0.01 to 0.46; RR 0.74, 95% CI 0.54 to 1.01; 5 RCTs, 171 participants; very low-certainty evidence) and RSV-associated MAARI with VE of 38% (95% CI -0.24 to 0.69; RR 0.62, 95% CI 0.31 to 1.24; 5 RCTs, 192 participants; very low-certainty evidence). There may be little to no difference in SAEs related to vaccination (low-certainty evidence). RSV recombinant F nanoparticle vaccine versus placebo in women of childbearing age The evidence is very uncertain regarding new RSV infections with VE of 50% (95% CI 0.08 to 0.73; RR 0.50, 95% CI 0.27 to 0.92; 1 RCT, 300 participants; very low-certainty evidence). There may be little to no difference in mortality from illness caused by RSV, all-cause mortality, and SAEs related to vaccination (low-certainty evidence). Phase III trials consistently demonstrated low risk of bias. Whilst phase I and II trials occasionally raised concerns about selection bias in the randomisation process, the overall evidence was deemed robust.

Authors' conclusions: RSV prefusion vaccines reduced RSV-associated lower respiratory tract illness and acute respiratory illness in older adults. There may be little to no difference in SAEs related to vaccination in older adults. Maternal vaccination with RSV F protein-based vaccines reduced medically attended RSV-associated lower respiratory tract illness and severe cases in infants. There may be little to no difference in SAEs related to vaccination in mothers and infants. The evidence is very uncertain regarding the effects of RSV vaccine on women of childbearing age, and the effects of live-attenuated RSV vaccines on infants and children; there may be little to no difference in SAEs related to vaccination.

Funding: This review was funded by the EU4Health Programme under a service contract with the European Health and Digital Executive Agency (HaDEA).

Registration: The review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42023439128).

This COVID-19 outpatient randomized controlled trials (RCTs) systematic review compares hospitalization outcomes amongst four treatment classes over pandemic period, geography, variants, and vaccine status. Outpatient RCTs with hospitalization endpoint were identified in Pubmed searches through May 2023, excluding RCTs <30 participants (PROSPERO-CRD42022369181). Risk of bias was extracted from COVID-19-NMA, with odds ratio utilized for pooled comparison. Searches identified 281 studies with 61 published RCTs for 33 diverse interventions analyzed. RCTs were largely unvaccinated cohorts with at least one COVID-19 hospitalization risk factor. Grouping by class, monoclonal antibodies (mAbs) (OR = 0.31 [95% CI = 0.24-0.40]) had highest hospital reduction efficacy, followed by COVID-19 convalescent plasma (CCP) (OR = 0.69 [95% CI = 0.53-0.90]), small molecule antivirals (OR = 0.78 [95% CI = 0.48-1.33]), and repurposed drugs (OR = 0.82 [95% CI: 0.72-0.93]). Earlier in disease onset interventions performed better than later. This meta-analysis allows approximate head-to-head comparisons of diverse outpatient interventions. Omicron sublineages (XBB and BQ.1.1) are resistant to mAbs Despite trial heterogeneity, this pooled comparison by intervention class indicated oral antivirals are the preferred outpatient treatment where available, but intravenous interventions from convalescent plasma to remdesivir are also effective and necessary in constrained medical resource settings or for acute and chronic COVID-19 in the immunocompromised.

Objectives The Salt Substitute and Stroke Study (SSaSS) recently reported blood pressure-mediated benefits of a potassium-enriched salt substitute on cardiovascular outcomes and death. This study assessed the effects of salt substitutes on a breadth of outcomes to quantify the consistency of the findings and understand the likely generalisability of the SSaSS results.

Methods We searched PubMed, Embase and the Cochrane Library up to 31 August 2021. Parallel group, step-wedge or cluster randomised controlled trials reporting the effect of salt substitute on blood pressure or clinical outcomes were included. Meta-analyses and metaregressions were used to define the consistency of findings across trials, geographies and patient groups.

Results There were 21 trials and 31 949 participants included, with 19 reporting effects on blood pressure and 5 reporting effects on clinical outcomes. Overall reduction of systolic blood pressure (SBP) was −4.61 mm Hg (95% CI −6.07 to −3.14) and of diastolic blood pressure (DBP) was −1.61 mm Hg (95% CI −2.42 to −0.79). Reductions in blood pressure appeared to be consistent across geographical regions and population subgroups defined by age, sex, history of hypertension, body mass index, baseline blood pressure, baseline 24-hour urinary sodium and baseline 24-hour urinary potassium (all p homogeneity >0.05). Metaregression showed that each 10% lower proportion of sodium choloride in the salt substitute was associated with a −1.53 mm Hg (95% CI −3.02 to −0.03, p=0.045) greater reduction in SBP and a −0.95 mm Hg (95% CI −1.78 to −0.12, p=0.025) greater reduction in DBP. There were clear protective effects of salt substitute on total mortality (risk ratio (RR) 0.89, 95% CI 0.85 to 0.94), cardiovascular mortality (RR 0.87, 95% CI 0. 81 to 0.94) and cardiovascular events (RR 0.89, 95% CI 0.85 to 0.94).

Conclusions The beneficial effects of salt substitutes on blood pressure across geographies and populations were consistent. Blood pressure-mediated protective effects on clinical outcomes are likely to be generalisable across population subgroups and to countries worldwide.

Objectives. To evaluate the evidence on benefits and harms of cannabinoids and similar plant-based compounds to treat chronic pain.

Data sources. Ovid® MEDLINE®, PsycINFO®, Embase®, the Cochrane Library, and SCOPUS® databases, reference lists of included studies, submissions received after Federal Register request were searched to July 2021.

Review methods. Using dual review, we screened search results for randomized controlled trials (RCTs) and observational studies of patients with chronic pain evaluating cannabis, kratom, and similar compounds with any comparison group and at least 1 month of treatment or followup. Dual review was used to abstract study data, assess study-level risk of bias, and rate the strength of evidence. Prioritized outcomes included pain, overall function, and adverse events. We grouped studies that assessed tetrahydrocannabinol (THC) and/or cannabidiol (CBD) based on their THC to CBD ratio and categorized them as high-THC to CBD ratio, comparable THC to CBD ratio, and low-THC to CBD ratio. We also grouped studies by whether the product was a whole-plant product (cannabis), cannabinoids extracted or purified from a whole plant, or synthetic. We conducted meta-analyses using the profile likelihood random effects model and assessed between-study heterogeneity using Cochran’s Q statistic chi square and the I2 test for inconsistency. Magnitude of benefit was categorized into no effect or small, moderate, and large effects.

Results. From 2,850 abstracts, 20 RCTs (N=1,776) and 7 observational studies (N=13,095) assessing different cannabinoids were included; none of kratom. Studies were primarily short term, and 75 percent enrolled patients with a variety of neuropathic pain. Comparators were primarily placebo or usual care. The strength of evidence (SOE) was low, unless otherwise noted. Compared with placebo, comparable THC to CBD ratio oral spray was associated with a small benefit in change in pain severity (7 RCTs, N=632, 0 to10 scale, mean difference [MD] −0.54, 95% confidence interval [CI] −0.95 to −0.19, I2=28%; SOE: moderate) and overall function (6 RCTs, N=616, 0 to 10 scale, MD −0.42, 95% CI −0.73 to −0.16, I2=24%). There was no effect on study withdrawals due to adverse events. There was a large increased risk of dizziness and sedation and a moderate increased risk of nausea (dizziness: 6 RCTs, N=866, 30% vs. 8%, relative risk [RR] 3.57, 95% CI 2.42 to 5.60, I2=0%; sedation: 6 RCTs, N=866, 22% vs. 16%, RR 5.04, 95% CI 2.10 to 11.89, I2=0%; and nausea: 6 RCTs, N=866, 13% vs. 7.5%, RR 1.79, 95% CI 1.20 to 2.78, I2=0%). Synthetic products with high-THC to CBD ratios were associated with a moderate improvement in pain severity, a moderate increase in sedation, and a large increase in nausea (pain: 6 RCTs, N=390 to 10 scale, MD −1.15, 95% CI −1.99 to −0.54, I2=39%; sedation: 3 RCTs, N=335, 19% vs. 10%, RR 1.73, 95% CI 1.03 to 4.63, I2=0%; nausea: 2 RCTs, N=302, 12% vs. 6%, RR 2.19, 95% CI 0.77 to 5.39; I²=0%). We found moderate SOE for a large increased risk of dizziness (2 RCTs, 32% vs. 11%, RR 2.74, 95% CI 1.47 to 6.86, I2=0%). Extracted whole-plant products with high-THC to CBD ratios (oral) were associated with a large increased risk of study withdrawal due to adverse events (1 RCT, 13.9% vs. 5.7%, RR 3.12, 95% CI 1.54 to 6.33) and dizziness (1 RCT, 62.2% vs. 7.5%, RR 8.34, 95% CI 4.53 to 15.34). We observed a moderate improvement in pain severity when combining all studies of high-THC to CBD ratio (8 RCTs, N=684, MD −1.25, 95% CI −2.09 to −0.71, I2=50%; SOE: moderate). Evidence on whole-plant cannabis, topical CBD, low-THC to CBD, other cannabinoids, comparisons with active products, and impact on use of opioids was insufficient to draw conclusions. Other important harms (psychosis, cannabis use disorder, and cognitive effects) were not reported.

Conclusions. Low to moderate strength evidence suggests small to moderate improvements in pain (mostly neuropathic), and moderate to large increases in common adverse events (dizziness, sedation, nausea) and study withdrawal due to adverse events with high- and comparable THC to CBD ratio extracted cannabinoids and synthetic products in short-term treatment (1 to 6 months). Evidence for whole-plant cannabis, and other comparisons, outcomes, and PBCs were unavailable or insufficient to draw conclusions. Small sample sizes, lack of evidence for moderate and long-term use and other key outcomes, such as other adverse events and impact on use of opioids during treatment, indicate that more research is needed.