After the recent announcement of COVID-19 vaccine efficacy in clinical trials by several manufacturers for protection against severe disease, a comprehensive post-efficacy strategy for the next steps to ensure vaccination of the global population is now required. These considerations should include how to manufacture billions of doses of high-quality vaccines, support for vaccine purchase, coordination of supply, the equitable distribution of vaccines and the logistics of global vaccine delivery, all of which are a prelude to a massive vaccination campaign targeting people of all ages. Furthermore, additional scientific questions about the vaccines remain that should be answered to improve vaccine efficacy, including questions regarding the optimization of vaccination regimens, booster doses, the correlates of protection, vaccine effectiveness, safety and enhanced surveillance. The timely and coordinated execution of these post-efficacy tasks will bring the pandemic to an effective, and efficient, close.

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Looking beyond COVID-19 vaccine phase 3 trials.

BACKGROUND
Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations.


METHODS
We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I(2) and χ(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure.


FINDINGS
We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0·32, 95% CI 0·19-0·52) and anogenital warts decreased significantly by 61% (0·39, 0·22-0·71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0·72, 95% CI 0·54-0·96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0·66 [95% CI 0·47-0·91]) and in women 20-39 years of age (0·68 [95% CI 0·51-0·89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0·50, 95% CI 0·34-0·74]) and in anogenital warts (0·86 [95% CI 0·79-0·94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects.


INTERPRETATION
Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement.


FUNDING
The Canadian Institutes of Health Research.

Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis

BACKGROUND:Rotavirus results in more diarrhoea-related deaths in children under five years than any other single agent in countries with high childhood mortality. It is also a common cause of diarrhoea-related hospital admissions in countries with low childhood mortality. Rotavirus vaccines that have been prequalified by the World Health Organization (WHO) include a monovalent vaccine (RV1; Rotarix, GlaxoSmithKline), a pentavalent vaccine (RV5; RotaTeq, Merck), and, more recently, another monovalent vaccine (Rotavac, Bharat Biotech). OBJECTIVES:To evaluate rotavirus vaccines prequalified by the WHO (RV1, RV5, and Rotavac) for their efficacy and safety in children. SEARCH METHODS:On 4 April 2018 we searched MEDLINE (via PubMed), the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (published in the Cochrane Library), Embase, LILACS, and BIOSIS. We also searched the WHO ICTRP, ClinicalTrials.gov, clinical trial reports from manufacturers' websites, and reference lists of included studies and relevant systematic reviews. SELECTION CRITERIA:We selected randomized controlled trials (RCTs) in children comparing rotavirus vaccines prequalified for use by the WHO versus placebo or no intervention. DATA COLLECTION AND ANALYSIS:Two review authors independently assessed trial eligibility and assessed risks of bias. One review author extracted data and a second author cross-checked them. We combined dichotomous data using the risk ratio (RR) and 95% confidence interval (CI). We stratified the analysis by country mortality rate and used GRADE to evaluate evidence certainty. MAIN RESULTS:Fifty-five trials met the inclusion criteria and enrolled a total of 216,480 participants. Thirty-six trials (119,114 participants) assessed RV1, 15 trials (88,934 participants) RV5, and four trials (8432 participants) Rotavac. RV1 Children vaccinated and followed up the first year of life In low-mortality countries, RV1 prevents 84% of severe rotavirus diarrhoea cases (RR 0.16, 95% CI 0.09 to 0.26; 43,779 participants, 7 trials; high-certainty evidence), and probably prevents 41% of cases of severe all-cause diarrhoea (RR 0.59, 95% CI 0.47 to 0.74; 28,051 participants, 3 trials; moderate-certainty evidence). In high-mortality countries, RV1 prevents 63% of severe rotavirus diarrhoea cases (RR 0.37, 95% CI 0.23 to 0.60; 6114 participants, 3 trials; high-certainty evidence), and 27% of severe all-cause diarrhoea cases (RR 0.73, 95% CI 0.56 to 0.95; 5639 participants, 2 trials; high-certainty evidence). Children vaccinated and followed up for two years In low-mortality countries, RV1 prevents 82% of severe rotavirus diarrhoea cases (RR 0.18, 95% CI 0.14 to 0.23; 36,002 participants, 9 trials; high-certainty evidence), and probably prevents 37% of severe all-cause diarrhoea episodes (rate ratio 0.63, 95% CI 0.56 to 0.71; 39,091 participants, 2 trials; moderate-certainty evidence). In high-mortality countries RV1 probably prevents 35% of severe rotavirus diarrhoea cases (RR 0.65, 95% CI 0.51 to 0.83; 13,768 participants, 2 trials; high-certainty evidence), and 17% of severe all-cause diarrhoea cases (RR 0.83, 95% CI 0.72 to 0.96; 2764 participants, 1 trial; moderate-certainty evidence). No increased risk of serious adverse events (SAE) was detected (RR 0.88 95% CI 0.83 to 0.93; high-certainty evidence). There were 30 cases of intussusception reported in 53,032 children after RV1 vaccination and 28 cases in 44,214 children after placebo or no intervention (RR 0.70, 95% CI 0.46 to 1.05; low-certainty evidence). RV5 Children vaccinated and followed up the first year of life In low-mortality countries, RV5 probably prevents 92% of severe rotavirus diarrhoea cases (RR 0.08, 95% CI 0.03 to 0.22; 4132 participants, 5 trials; moderate-certainty evidence). We did not identify studies reporting on severe all-cause diarrhoea in low-mortality countries. In high-mortality countries, RV5 prevents 57% of severe rotavirus diarrhoea (RR 0.43, 95% CI 0.29 to 0.62; 5916 participants, 2 trials; high-certainty evidence), but there is probably little or no difference between vaccine and placebo for severe all-cause diarrhoea (RR 0.80, 95% CI 0.58 to 1.11; 1 trial, 4085 participants; moderate-certainty evidence). Children vaccinated and followed up for two years In low-mortality countries, RV5 prevents 82% of severe rotavirus diarrhoea cases (RR 0.18, 95% CI 0.08 to 0.39; 7318 participants, 4 trials; moderate-certainty evidence). We did not identify studies reporting on severe all-cause diarrhoea in low-mortality countries. In high-mortality countries, RV5 prevents 41% of severe rotavirus diarrhoea cases (RR 0.59, 95% CI 0.43 to 0.82; 5885 participants, 2 trials; high-certainty evidence), and 15% of severe all-cause diarrhoea cases (RR 0.85, 95% CI 0.75 to 0.98; 5977 participants, 2 trials; high-certainty evidence). No increased risk of serious adverse events (SAE) was detected (RR 0.93 95% CI 0.86 to 1.01; moderate to high-certainty evidence). There were 16 cases of intussusception in 43,629 children after RV5 vaccination and 20 cases in 41,866 children after placebo (RR 0.77, 95% CI 0.41 to 1.45; low-certainty evidence). Rotavac Children vaccinated and followed up the first year of life Rotavac has not been assessed in any RCT in countries with low child mortality. In India, a high-mortality country, Rotavac probably prevents 57% of severe rotavirus diarrhoea cases (RR 0.43, 95% CI 0.30 to 0.60; 6799 participants, moderate-certainty evidence); the trial did not report on severe all-cause diarrhoea at one-year follow-up. Children vaccinated and followed up for two years Rotavac probably prevents 54% of severe rotavirus diarrhoea cases in India (RR 0.46, 95% CI 0.35 to 0.60; 6541 participants, 1 trial; moderate-certainty evidence), and 16% of severe all-cause diarrhoea cases (RR 0.84, 95% CI 0.71 to 0.98; 6799 participants, 1 trial; moderate-certainty evidence). No increased risk of serious adverse events (SAE) was detected (RR 0.93 95% CI 0.85 to 1.02; moderate-certainty evidence). There were eight cases of intussusception in 5764 children after Rotavac vaccination and three cases in 2818 children after placebo (RR 1.33, 95% CI 0.35 to 5.02; very low-certainty evidence). There was insufficient evidence of an effect on mortality from any rotavirus vaccine (198,381 participants, 44 trials; low- to very low-certainty evidence), as the trials were not powered to detect an effect at this endpoint. AUTHORS' CONCLUSIONS:RV1, RV5, and Rotavac prevent episodes of rotavirus diarrhoea. Whilst the relative effect estimate is smaller in high-mortality than in low-mortality countries, there is a greater number of episodes prevented in these settings as the baseline risk is much higher. We found no increased risk of serious adverse events.

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Vaccines for preventing rotavirus diarrhoea: vaccines in use

Immune checkpoints are small molecules expressed by immune cells that play critical roles in maintaining immune homeostasis. Targeting the immune checkpoints cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1) with inhibitory antibodies has demonstrated effective and durable antitumor activity in subgroups of patients with cancer. The US Food and Drug Administration has approved several immune checkpoint inhibitors (ICPis) for the treatment of a broad spectrum of malignancies. Endocrinopathies have emerged as one of the most common immune-related adverse events (irAEs) of ICPi therapy. Hypophysitis, thyroid dysfunction, insulin-deficient diabetes mellitus, and primary adrenal insufficiency have been reported as irAEs due to ICPi therapy. Hypophysitis is particularly associated with anti-CTLA-4 therapy, whereas thyroid dysfunction is particularly associated with anti-PD-1 therapy. Diabetes mellitus and primary adrenal insufficiency are rare endocrine toxicities associated with ICPi therapy but can be life-threatening if not promptly recognized and treated. Notably, combination anti-CTLA-4 and anti-PD-1 therapy is associated with the highest incidence of ICPi-related endocrinopathies. The precise mechanisms underlying these endocrine irAEs remain to be elucidated. Most ICPi-related endocrinopathies occur within 12 weeks after the initiation of ICPi therapy, but several have been reported to develop several months to years after ICPi initiation. Some ICPi-related endocrinopathies may resolve spontaneously, but others, such as central adrenal insufficiency and primary hypothyroidism, appear to be persistent in most cases. The mainstay of management of ICPi-related endocrinopathies is hormone replacement and symptom control. Further studies are needed to determine (i) whether high-dose corticosteroids in the treatment of ICPi-related endocrinopathies preserves endocrine function (especially in hypophysitis), and (ii) whether the development of ICPi-related endocrinopathies correlates with tumor response to ICPi therapy.

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Endocrine Toxicity of Cancer Immunotherapy Targeting Immune Checkpoints.

Cell-free DNA (cfDNA) refers to short fragments of acellular nucleic acids detectable in almost all body fluids, including blood, and is involved in various physiological and pathological phenomena such as immunity, coagulation, aging, and cancer. In cancer patients, a fraction of hematogenous cfDNA originates from tumors, termed circulating tumor DNA (ctDNA), and may carry the same mutations and genetic alterations as those of a primary tumor. Thus, ctDNA potentially provides an opportunity for noninvasive assessment of cancer. Recent advances in ctDNA analysis methods will potentially lead to the development of a liquid biopsy tool for the diagnosis, prognosis, therapy response monitoring, and tracking the rise of new mutant sub-clones in cancer patients. Over the past few decades, cancer-specific mutations in ctDNA have been detected using a variety of untargeted methods such as digital karyotyping, personalized analysis of rearranged ends (PARE), whole-genome sequencing of ctDNA, and targeted approaches such as conventional and digital PCR-based methods and deep sequencing-based technologies. More recently, several chip-based electrochemical sensors have been developed for the analysis of ctDNA in patient samples. This paper aims to comprehensively review the diagnostic, prognostic, and predictive potential of ctDNA as a minimally invasive liquid biopsy for cancer patients. We also present an overview of current advances in the analytical sensitivity and accuracy of ctDNA analysis methods as well as biological and technical challenges, which need to be resolved for the integration of ctDNA analysis into routine clinical practice.

Circulating tumor DNA and liquid biopsy: opportunities, challenges, and recent advances in detection technologies

Objective Hepatitis D virus (HDV) is a defective virus that completes its life cycle only with hepatitis B virus (HBV). The HBV with HDV super-infection has been considered as one of the most severe forms of the chronic viral hepatitis. However, there is a scarcity of data on the global burden of HDV infection. Design We searched PubMed, Embase, Cochrane Library and China Knowledge Resource Integrated databases from 1 January 1977 to 31 December 2016. We included studies with a minimum sample size of 50 patients. Our study analysed data from a total of 40 million individuals to estimate the prevalence of HDV by using Der-Simonian Laird random-effects model. The data were further categorised according to risk factors. Results From a total of 2717 initially identified studies, only 182 articles from 61 countries and regions met the final inclusion criteria. The overall prevalence of HDV was 0.98% (95% CI 0.61 to 1.42). In HBsAg-positive population, HDV pooled prevalence was 14.57% (95% CI 12.93 to 16.27): Seroprevalence was 10.58% (95% CI 9.14 to 12.11) in mixed population without risk factors of intravenous drug use (IVDU) and high-risk sexual behaviour (HRSB). It was 37.57% (95% CI 29.30 to 46.20) in the IVDU population and 17.01% (95% CI 10.69 to 24.34) in HRSB population. Conclusion We found that approximately 10.58% HBsAg carriers (without IVDU and HRSB) were coinfected with HDV, which is twofold of what has been estimated before. We also noted a substantially higher HDV prevalence in the IVDU and HRSB population. Our study highlights the need for increased focus on the routine HDV screening and rigorous implementation of HBV vaccine programme.

https://gut.bmj.com/content/gutjnl/early/2018/09/18/gutjnl-2018-316601.full.pdf

Prevalence and burden of hepatitis D virus infection in the global population: a systematic review and meta-analysis

Importance The conclusions from the multiple randomized clinical trials exploring the relationship between development of intussusception and rotavirus vaccination among neonates and infants have been controversial. Objective To evaluate the association between rotavirus vaccination and risk of intussusception. Data Sources For this systematic review and meta-analysis, PubMed, Web of Science, Cochrane library, and Embase databases were searched from January 1, 1999, through December 31, 2018, using no language restrictions. The search terms wererotavirusorRV(rotavirus vaccine) orHRV(human rotavirus vaccine),vaccin*, andintussusception. Study Selection Randomized clinical trials of neonates and infants that compared the risk of intussusception after the vaccination with a placebo group were included. Data Extraction and Synthesis A fixed-effects model was used to pool the data. Statistical heterogeneity was assessed with Q test andI2statistic; relative risk (RR), risk difference (RD), and 95% CIs were calculated using the Mantel-Haenszel method. Main Outcomes and Measures The main outcome was the diagnosis of intussusception in the analysis. The pooled and subtotal results of RR, RD, and 95% CI for the risk of intussusception were estimated at 31 days, 1 year, and 2 years after vaccination. Results A total of 25 randomized clinical trials including 200 594 participants (104 647 receiving vaccine and 95 947 receiving placebo) in 33 countries from 4 continents were included in this meta-analysis. Twenty cases of definite intussusception were diagnosed within 31 days after rotavirus vaccination, with 11 cases (55%) in the vaccine group and 9 cases (45%) in the placebo group (RD, 0.17 per 10 000 infants [95% CI, −1.16 to 1.50 per 10 000 infants],P = .80; RR, 1.14 [95% CI, 0.49 to 2.64],P = .77). Seventy-four cases were reported within 1 year, with 37 cases (50%) in the vaccine group and 37 cases (50%) in the placebo group (RD, −0.65 per 10 000 infants [95% CI, −2.68 to 1.39 per 10 000 infants],P = .53; RR, 0.84 [95% CI, 0.53 to 1.32],P = .45). Fifty-nine cases were reported within 2 years, with 29 cases (49%) in the vaccine group and 30 cases (51%) in the placebo group (RD, −0.48 per 10 000 infants [95% CI, −3.64 to 2.69 per 10 000 infants],P = .77; RR, 0.91 [95% CI, 0.55 to 1.52],P = .73). Conclusions and Relevance Results of this systematic review and meta-analysis suggest that monovalent, pentavalent, monovalent human-bovine, oral bovine pentavalent, and human neonatal rotavirus vaccination was not associated with an elevated risk of intussusception among neonates or infants.

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Association Between Rotavirus Vaccination and Risk of Intussusception Among Neonates and Infants: A Systematic Review and Meta-analysis.

We sincerely appreciate Stockdale and colleagues1 for their critical consideration of our article. Herein, we tried to answer their concerns about the methodology of our meta-analysis.2 

We used hepatitis D virus (HDV) antibody (both IgM and IgG) seropositivity as a measure of overall burden of HDV seroprevalence. Although anti-HDV IgM Ab assays may fail to detect low titres of antibodies and underestimate HDV seroprevalence,3 patients with a negative anti-HDV IgM results are less likely to progress into clinical disease.4 Majority of the included studies in our article used anti-HDV antibody assays and only two mentioned the use of RNA assays for the prevalence of HDV. Therefore, considering the wide application of the anti-HDV antibody assay as a measure of HDV seroprevalence,5 we used the similar method in our meta-analysis.

We do not think it would be correct to extrapolate the prevalence of HBsAg based on our estimates of HDV seroprevalence among general population and mixed population (HBsAg carriers without risk factors such as intravenous drug use and high-risk sexual behaviours). This is because the general population and the mixed …

https://gut.bmj.com/content/gutjnl/early/2019/04/09/gutjnl-2019-318691.full.pdf

Hepatitis D: not a rare disease anymore: global update for 2017–2018

Importance Rotavirus vaccines have been introduced worldwide, and the clinical association of different rotavirus vaccines with reduction in rotavirus gastroenteritis (RVGE) after introduction are noteworthy. Objective To evaluate the comparative benefit, risk, and immunogenicity of different rotavirus vaccines by synthesizing randomized clinical trials (RCTs) and observational studies. Data Sources Relevant studies published in 4 databases: Embase, PubMed, the Cochrane Library, and Web of Science were searched until July 1, 2020, using search terms including “rotavirus” and “vaccin*.” Study Selection Randomized clinical trials and cohort and case-control studies involving more than 100 children younger than 5 years that reported the effectiveness, safety, or immunogenicity of rotavirus vaccines were included. Data Extraction and Synthesis A random-effects model was used to calculate relative risks (RRs), odds ratios (ORs), risk differences, and 95% CIs. Adjusted indirect treatment comparison was performed to assess the differences in the protection of Rotarix and RotaTeq. Main Outcomes and Measures The primary outcomes were RVGE, severe RVGE, and RVGE hospitalization. Safety-associated outcomes involved serious adverse events, intussusception, and mortality. Results A meta-analysis of 20 RCTs and 38 case-control studies revealed that Rotarix (RV1) significantly reduced RVGE (RR, 0.316 [95% CI, 0.224-0.345]) and RVGE hospitalization risk (OR, 0.347 [95% CI, 0.279-0.432]) among children fully vaccinated; RotaTeq (RV5) had similar outcomes (RVGE: RR, 0.350 [95% CI, 0.275-0.445]; RVGE hospitalization risk: OR, 0.272 [95% CI, 0.197-0.376]). Rotavirus vaccines also demonstrated higher protection against severe RVGE. Additionally, no significant differences in the protection of RV1 and RV5 against rotavirus disease were noted in adjusted indirect comparisons. Moderate associations were found between reduced RVGE risk and Rotavac (RR, 0.664 [95% CI, 0.548-0.804]), Rotasiil (RR, 0.705 [95% CI, 0.605-0.821]), and Lanzhou lamb rotavirus vaccine (RR, 0.407 [95% CI, 0.332-0.499]). All rotavirus vaccines demonstrated no risk of serious adverse events. A positive correlation was also found between immunogenicity and vaccine protection (eg, association of RVGE with RV1: coefficient, −1.599; adjustedR2, 99.7%). Conclusions and Relevance The high protection and low risk of serious adverse events for rotavirus vaccines in children who were fully vaccinated emphasized the importance of worldwide introduction of rotavirus vaccination. Similar protection provided by Rotarix and RotaTeq relieves the pressure of vaccines selection for health care authorities.

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Association of Rotavirus Vaccines With Reduction in Rotavirus Gastroenteritis in Children Younger Than 5 Years: A Systematic Review and Meta-analysis of Randomized Clinical Trials and Observational Studies.

Hemophagocytic Lymphohistiocytosis (HLH) is a rare clinical syndrome with high mortality rate. The diagnosis of HLH draws on a constellation of clinical and laboratory abnormalities including extremely high serum ferritin levels. However, no biomarker has been firmly established as a clinically useful prognostic tool in HLH patients. We aimed to perform a retrospective analysis of two independent cohorts to explore the prognostic value of discharge serum ferritin for newly diagnosed adult HLH patients who recently started treatment. The prognostic value of serum ferritin levels at discharge (will be called as post-treatment ferritin level) was initially evaluated in a “test cohort” of 161 previously untreated consecutive adult HLH patients. It was then validated in a second cohort of 68 consecutive previously untreated patients (validation cohort). Multivariate analysis revealed that significantly high post-treatment serum ferritin levels (>1050 μg/L) were associated with a higher risk of death and poor overall survival in the test cohort (hazard ratio (HR): 3.176, 95% confidence interval (CI) 1.468–6.869, P = 0.003), and the validation cohort (HR: 13.412, 95%CI 1.716–104.816, P = 0.013). At 6-month follow-up period in the test cohort, patients with a > 81% decrease in the serum ferritin level had a significantly higher probability of survival when compared with the patients with ≥14% increase in the serum ferritin level (94% vs. 31%, P < 0.001). Similar findings were observed on the analysis of the decrease in the serum ferritin level in the validation cohort. These results suggest that the serum ferritin level can be used as an independent prognostic marker in the adult HLH patients.

/pdf/development-and-validation-of-the-prognostic-value-of-2pfztek53b.pdf

Hua-Guo Xu

Papers

Prevalence and burden of hepatitis D virus infection in the global population: a systematic review and meta-analysis

Association Between Rotavirus Vaccination and Risk of Intussusception Among Neonates and Infants: A Systematic Review and Meta-analysis.

Hepatitis D: not a rare disease anymore: global update for 2017–2018

Association of Rotavirus Vaccines With Reduction in Rotavirus Gastroenteritis in Children Younger Than 5 Years: A Systematic Review and Meta-analysis of Randomized Clinical Trials and Observational Studies.

Development and validation of the prognostic value of ferritin in adult patients with Hemophagocytic Lymphohistiocytosis.