Re-evaluating herd protection by Vi typhoid vaccine in a cluster randomized trial

Background

In a cluster randomized trial (CRT) of a Vi polysaccharide vaccine against typhoid in the slums of Kolkata we found evidence of vaccine herd protection. However, transmission of typhoid into clusters from the outside likely occurred in this densely populated setting, which could have diminished our estimates of vaccine herd protection.

Methods

Eighty clusters (40 in each arm) were randomised to receive a single dose of either Vi or inactivated hepatitis A vaccine. We analysed protection for the entire cluster and for subclusters consisting of residents of the innermost households.

Results

During 2 y of follow-up, total protection was 61% (95% CI 41 to 75), overall protection was 57% (95% CI 37 to 71) and indirect protection was 44% (95% CI 2 to 69). Analyses of the innermost 75% and 50% of households of the clusters showed similar findings. However, in the innermost 25% of households of the clusters, total protection was 82% (95% CI 48 to 94) and overall protection was 66% (95% CI 27 to 84). There was not a sufficient sample size to demonstrate such a trend for indirect protection in these innermost households.

Conclusions

The findings suggest that analyses of the entire cluster may have led to underestimation of herd protection against typhoid by Vi vaccine and that restriction of the analyses to the inner subclusters may have led to a more accurate estimation of vaccine herd effects.

A randomized Phase I/II study to evaluate safety and reactogenicity of a heat-stable rotavirus vaccine in healthy adults followed by evaluation of the safety, reactogenicity, and immunogenicity in infants

Objectives: To assess the safety and reactogenicity of single oral dose of heat-stable rotavirus vaccine (HSRV) in healthy adults aged 18–45 years followed by assessment of safety, reactogenicity, and immunogenicity of three doses of HSRV in healthy infants aged 6–8 weeks at enrollment.

Trial Design: Single-center randomized controlled, sequential, blinded (adults) and open-label (infants).

Setting: Single site at International Center for Diarrheal Disease Research, Bangladesh (icddr,b).

Participants: Fifty eligible adults randomized in 1:1 ratio (HSRV: Placebo) followed by 50 eligible infants randomized in 1:1 ratio (HSRV: Comparator (RotaTeq®, pentavalent human-bovine (WC3) reassortant live-attenuated, rotavirus vaccine)).

Intervention: Adults received either a single dose of HSRV or placebo and followed for 14 days. Infants received three doses of either HSRV or comparator with a follow-up for 28 days after each dose.

Main Outcome Measures: Solicited and unsolicited adverse events (AEs) along with any serious adverse events (SAEs) were part of the safety and reactogenicity assessment in adults and infants whereas serum anti-rotavirus IgA response rates were part of immunogenicity assessment in infants only. Post-vaccination fecal shedding of vaccine-virus rotavirus strains was also determined in adults and infants.

Results: In this study, HSRV, when compared with placebo, did not result in increase in solicited adverse events (solicited AEs) in adults. In infants, HSRV had a safety profile similar to comparator vis-à-vis solicited AEs. In infants, fecal shedding of vaccine-virus strains was not detected in HSRV recipients but was observed in two comparator recipients. Percentage of infants exhibiting threefold rise in serum anti-rotavirus IgA titers from baseline to 1-month post-dose 3 in HSRV group was 88% (22/25) and 84% (21/25) in comparator group.

Conclusion: HSRV was found to be generally well-tolerated in both adults and infants and immunogenic in infants.

Impact of vaccination on the risk factors for acute rotavirus diarrhea: An analysis of the data of a cluster randomized trial conducted in a rural area of Bangladesh

BACKGROUND

Rotavirus is one of the causes of severe diarrhea and death in young children. To control the disease, safe and effective vaccines are being used in several countries. We assessed the impact of vaccination on the risk factors for acute rotavirus diarrhea (ARD) in Bangladesh.

METHODS

We used the data of a cluster-randomized trial. The clusters were 142 villages, 71 in each of the two arms of study. The infants were offered human rotavirus vaccine (HRV), Rotarix, over three-year period. We divided the time period into two equal periods (T1 and T2). A generalized estimating equation with logit-link function was used to evaluate the risk factors by arm and by period.

RESULTS

Among 10,917 children, 5,759 (53%) were in the HRV villages. We had 359 cases; 44% in the HRV villages. Mean age of attack was similar between the arms of study in T1, but significantly higher in HRV villages than that in the non-HRV villages in T2. In HRV villages, males were at a higher risk of having ARD than females in T1, but not in T2. In contrast, males were at a higher risk of having ARD in both the time periods in non-HRV villages. In HRV-villages, children having literate mother were at significantly higher risk of having ARD in T1 but not in T2; whereas children in the non-HRV villages had a higher risk of having ARD in T2. Children living in an area with higher phone users had more cases than their counterpart in non-HRV villages, but not in HRV villages.

CONCLUSION

Our study illustrates that several risk factors for ARD varied between the two arms of study as well as between the two periods of study. Assessing post-vaccination risk factors is, therefore, important for understanding the impact of vaccination and undertaking post-vaccination control measures.

HEV study protocol : design of a cluster-randomised, blinded trial to assess the safety, immunogenicity and effectiveness of the hepatitis E vaccine HEV 239 (Hecolin) in women of childbearing age in rural Bangladesh

INTRODUCTION

Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis in the developing world and is a public health problem, in particular among pregnant women, where it may lead to severe or fatal complications. A recombinant HEV vaccine, 239 (Hecolin; Xiamen Innovax Biotech, Xiamen, China), is licensed in China, but WHO calls for further studies to evaluate the safety and immunogenicity of this vaccine in vulnerable populations, and to evaluate protection in pregnancy. We are therefore conducting a phase IV trial to assess the effectiveness, safety and immunogenicity of the HEV 239 vaccine when given in women of childbearing age in rural Bangladesh, where HEV infection is endemic.

METHODS AND ANALYSIS

Enrolment of a target of approximately 20 000 non-pregnant women, aged 16-39 years, started on 2 October 2017 in Matlab, Bangladesh. Sixty-seven villages were randomised by village at a 1:1 ratio to receive either the HEV vaccine or the control vaccine (hepatitis B vaccine). A 3-dose vaccination series at 0, 1 and 6 months is ongoing, and women are followed up for 24 months. The primary outcome is confirmed HEV disease among pregnant women. After vaccination, participants are requested to report information about clinical hepatitis symptoms. Participants who become pregnant are visited at their homes every 2 weeks to collect information about pregnancy outcome and to screen for clinical hepatitis. All suspected hepatitis cases undergo laboratory testing for diagnostic evaluation. The incidence of confirmed HEV disease among pregnant and non-pregnant women will be compared between the HEV vaccinated and control groups, safety and immunogenicity of the vaccine will also be evaluated.

ETHICS AND DISSEMINATION

The protocol was reviewed and approved by the International Centre for Diarrhoeal Disease Research, Bangladesh Research Review Committee and Ethical Review Committee, and the Directorate General of Drug Administration in Bangladesh, and by the Regional Ethics Committee in Norway. This article is based on the protocol version 2.2 dated 29 June 2017. We will present the results through peer-reviewed publications and at international conferences.

TRIAL REGISTRATION NUMBER

The trial is registered at clinicaltrials.gov with the registry name "Effectiveness Trial to Evaluate Protection of Pregnant Women by Hepatitis E Vaccine in Bangladesh" and the identifier NCT02759991.

Can we 'WaSH' infectious diseases out of slums?

The world is becoming increasingly urban and most of this growth is taking place in urban slums of the developing world. The current (2019) global population stands at 7.7 billion, with approximately one billion (13%) living in urban slums. By 2030 the world's population is projected to grow to 8.5 billion, with an estimated two billion (24%) living in slums. Slums are typically overcrowded, with most residents sharing a single room with four to five family members. There is usually no formal sewage or waste disposal system. Open sewage, with antimicrobial-resistant organisms, typically flows just outside the door, which during the rainy season often enters the home and contaminates the household drinking source. Hygiene is difficult if not impossible to maintain, hence the significant burden of infectious diseases, especially those with a faecal-oral mode of transmission. Transmission is year-round and the leading enteric pathogens are rotavirus, Cryptosporidium, Shigella, Campylobacter, Salmonella typhi, and Vibrio cholera. Water, sanitation, and hygiene (WaSH) will be crucial components of a future integrated control strategy for infectious diseases in slums. Cheap WaSH interventions have been trialled, but their impact has been modest and short-lived. More expensive WaSH alternatives that will provide lasting change now need to be explored. Can we 'WaSH' infectious diseases out of slums?

Influence of the Interval between Antenatal Corticosteroid Therapy and Delivery on the Incidence of Respiratory Distress Syndrome in Neonate

In spite of the recommendation for rescue antenatal corticosteroids (ACS), the optimal time interval between primary and rescue courses has not been clearly demonstrated. The aim of this retrospective study was to determine the effects of the interval between a single ACS (Dexamethasone) course and delivery on the incidence of respiratory distress syndrome (RDS) in neonates at Mymensingh Medical College Hospital Center from 1st January 2017 to 30th June 2017. Injection Dexamethasone 2 doses (12.5mg IM 12 hourly for 2 doses) or 4 doses (6mg IM every 12 hours for 4 doses) use to arrest preterm labor as well as to prevent RDS delivered beyond 48 hours after ACS administration between 24 and 34 weeks gestation. The risk of RDS was compared between patients who delivered within seven days (Group I) and 7-14 days (Group II) after ACS administration. We included 140 and 60 patients in Group I and Group II respectively. After adjusting for confounders, the ACS delivery interval was significantly associated with RDS in Group II (adjusted odds ratio 12.8, 95% confidence interval 1.31-164.7). A longer ACS delivery interval is associated with a higher risk of RDS. Thus, the use of a rescue course could be expected to reduce the incidence of RDS in patients beyond seven days after ACS administration who remain at risk for preterm delivery within seven days, especially in cases of placenta previa and/or women bearing a male fetus.

1684. Clinical Profile and Outcome of Scrub Typhus-Related Acute Respiratory Distress Syndrome in Adults Presenting to a Tertiary Care Hospital in North India

Background

Methods

Results

Conclusion

Disclosures

Langley J, Leach A, Madhi SA, Maleux K, Lien-Anh Nguyen T, Puthanakit T, Silas P, Stoszek SK, Tangsathapornpong A, Teeratakulpisarn J, Virta M, Zaman K. 2855. Respiratory Syncytial Virus Neutralizing Antibodies in Cord Blood and Serum from Infants up to 2 Years of Age in a Multinational Prospective Study

Background

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections (LRTI) during infancy worldwide. High cord blood (CB) concentrations of anti-RSV neutralizing antibody (nAb) may attenuate, delay, or prevent infant infection. We report RSV A and B nAb concentrations in CB and serum from a birth cohort at different time points through 2 years of age.

Methods

Between 2013 and 2017, newborns from 8 countries were studied prospectively from birth to 2 years of age (NCT01995175). CB was collected at birth for the entire cohort. A subcohort of children was randomly assigned to have one blood sample collected again at either 2, 4, 6, 12, 18, or 24 months of age. Sera were analyzed for RSV A and B nAb concentrations by serum neutralization assay. Active surveillance was used to identify LRTIs during the 2-year follow-up as previously reported.

Results

In total, 2,401 newborns were enrolled and followed up. >99% of infants had detectable CB RSV A and B nAb. Geometric mean antibody titers (GMTs) varied by country, but were overall higher for RSV B than for RSV A (327 vs. 251; Figure 1). The lowest GMTs were seen from CB sera collected from South African newborns (197 RSV A, 255 RSV B); Canadian newborns had the highest RSV A GMT (383), while Hondurans had the highest RSV B GMT (460). 1380 infants provided follow-up serum nAb results as part of the subcohort (Figure 2). Dramatic waning of GMTs was evident, with a ~3-fold drop in GMTs at 2 months of age, and an additional ~2-fold drop between 2 and 4 months of age. At 6 and 12 months of age, 71% and 50% of infants had RSV A nAb and GMTs were at a nadir of 14. At 6, 12, and 18 months of age, RSV B nAb was detected in 98%, 69%, and 63% of infants, respectively. The RSV B nAb nadir GMT of 20 was observed at 12 months of age, while the 6- and 18-month RSV B nAb GMTs were 30 and 31, respectively. A total of 1,017 LRTIs were identified during the 2-year study period; of which, 94 (9%) were caused by RSV A and 132 (13%) by RSV B. Associations between CB nAb levels and RSV infection will be presented.

Conclusion

Neutralizing Ab to RSV A and B was present at birth in infants from 8 countries, and waned over time. GMTs were at a nadir at 6 to 12 months of age.

Funding. GlaxoSmithKline Biologicals SA.

Disclosures

All Authors: No reported Disclosures.

Causes of severe pneumonia requiring hospital admission in children without HIV infection from Africa and Asia: the PERCH multi-country case-control study

BACKGROUND

Pneumonia is the leading cause of death among children younger than 5 years. In this study, we estimated causes of pneumonia in young African and Asian children, using novel analytical methods applied to clinical and microbiological findings.

METHODS

We did a multi-site, international case-control study in nine study sites in seven countries: Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia. All sites enrolled in the study for 24 months. Cases were children aged 1-59 months admitted to hospital with severe pneumonia. Controls were age-group-matched children randomly selected from communities surrounding study sites. Nasopharyngeal and oropharyngeal (NP-OP), urine, blood, induced sputum, lung aspirate, pleural fluid, and gastric aspirates were tested with cultures, multiplex PCR, or both. Primary analyses were restricted to cases without HIV infection and with abnormal chest x-rays and to controls without HIV infection. We applied a Bayesian, partial latent class analysis to estimate probabilities of aetiological agents at the individual and population level, incorporating case and control data.

FINDINGS

Between Aug 15, 2011, and Jan 30, 2014, we enrolled 4232 cases and 5119 community controls. The primary analysis group was comprised of 1769 (41·8% of 4232) cases without HIV infection and with positive chest x-rays and 5102 (99·7% of 5119) community controls without HIV infection. Wheezing was present in 555 (31·7%) of 1752 cases (range by site 10·6-97·3%). 30-day case-fatality ratio was 6·4% (114 of 1769 cases). Blood cultures were positive in 56 (3·2%) of 1749 cases, and Streptococcus pneumoniae was the most common bacteria isolated (19 [33·9%] of 56). Almost all cases (98·9%) and controls (98·0%) had at least one pathogen detected by PCR in the NP-OP specimen. The detection of respiratory syncytial virus (RSV), parainfluenza virus, human metapneumovirus, influenza virus, S pneumoniae, Haemophilus influenzae type b (Hib), H influenzae non-type b, and Pneumocystis jirovecii in NP-OP specimens was associated with case status. The aetiology analysis estimated that viruses accounted for 61·4% (95% credible interval [CrI] 57·3-65·6) of causes, whereas bacteria accounted for 27·3% (23·3-31·6) and Mycobacterium tuberculosis for 5·9% (3·9-8·3). Viruses were less common (54·5%, 95% CrI 47·4-61·5 vs 68·0%, 62·7-72·7) and bacteria more common (33·7%, 27·2-40·8 vs 22·8%, 18·3-27·6) in very severe pneumonia cases than in severe cases. RSV had the greatest aetiological fraction (31·1%, 95% CrI 28·4-34·2) of all pathogens. Human rhinovirus, human metapneumovirus A or B, human parainfluenza virus, S pneumoniae, M tuberculosis, and H influenzae each accounted for 5% or more of the aetiological distribution. We observed differences in aetiological fraction by age for Bordetella pertussis, parainfluenza types 1 and 3, parechovirus-enterovirus, P jirovecii, RSV, rhinovirus, Staphylococcus aureus, and S pneumoniae, and differences by severity for RSV, S aureus, S pneumoniae, and parainfluenza type 3. The leading ten pathogens of each site accounted for 79% or more of the site's aetiological fraction.

INTERPRETATION

In our study, a small set of pathogens accounted for most cases of pneumonia requiring hospital admission. Preventing and treating a subset of pathogens could substantially affect childhood pneumonia outcomes.

FUNDING

Bill & Melinda Gates Foundation.

Quantifying the Impact of Natural Immunity on Rotavirus Vaccine Efficacy Estimates: A Clinical Trial in Dhaka, Bangladesh (PROVIDE) and a Simulation Study

Background

The low efficacy of rotavirus vaccines in clinical trials performed in low-resource settings may be partially explained by acquired immunity from natural exposure, especially in settings with high disease incidence.

Methods

In a clinical trial of monovalent rotavirus vaccine in Bangladesh, we compared the original per-protocol efficacy estimate to efficacy derived from a recurrent events survival model in which children were considered naturally exposed and potentially immune after their first rotavirus diarrhea (RVD) episode. We then simulated trial cohorts to estimate the expected impact of prior exposure on efficacy estimates for varying rotavirus incidence rates and vaccine efficacies.

Results

Accounting for natural immunity increased the per-protocol vaccine efficacy estimate against severe RVD from 63.1% (95% confidence interval [CI], 33.0%-79.7%) to 70.2% (95% CI, 44.5%-84.0%) in the postvaccination period, and original year 2 efficacy was underestimated by 14%. The simulations demonstrated that this expected impact increases linearly with RVD incidence, will be greatest for vaccine efficacies near 50%, and can reach 20% in settings with high incidence and low efficacy.

Conclusions

High rotavirus incidence leads to predictably lower vaccine efficacy estimates due to the acquisition of natural immunity in unvaccinated children, and this phenomenon should be considered when comparing efficacy estimates across settings.

Clinical Trials Registration

NCT01375647.

Immunogenicity of full and fractional dose of inactivated poliovirus vaccine for use in routine immunisation and outbreak response: an open-label, randomised controlled trial

BACKGROUND

Intradermal administration of fractional inactivated poliovirus vaccine (fIPV) is a dose-sparing alternative to the intramuscular full dose. We aimed to compare the immunogenicity of two fIPV doses versus one IPV dose for routine immunisation, and also assessed the immunogenicity of an fIPV booster dose for an outbreak response.

METHODS

We did an open-label, randomised, controlled, inequality, non-inferiority trial in two clinics in Dhaka, Bangladesh. Healthy infants were randomly assigned at 6 weeks to one of four groups: group A received IPV at age 14 weeks and IPV booster at age 22 weeks; group B received IPV at age 14 weeks and fIPV booster at age 22 weeks; group C received IPV at age 6 weeks and fIPV booster at age 22 weeks; and group D received fIPV at 6 weeks and 14 weeks and fIPV booster at age 22 weeks. IPV was administered by needle-syringe as an intramuscular full dose (0·5 mL), and fIPV was administered intradermally (0·1 mL of the IPV formulation was administered using the 0·1 mL HelmJect auto-disable syringe with a Helms intradermal adapter). Both IPV and fIPV were administered on the outer, upper right thigh of infants. The primary outcome was vaccine response to poliovirus types 1, 2, and 3 at age 22 weeks (routine immunisation) and age 26 weeks (outbreak response). Vaccine response was defined as seroconversion from seronegative (<1:8) at baseline to seropositive (≥1:8) or four-fold increase in reciprocal antibody titres adjusted for maternal antibody decay and was assessed in the modified intention-to-treat population (infants who received polio vaccines per group assignment and polio antibody titre results to serotypes 1, 2, and 3 at 6, 22, 23, and 26 weeks of age). The non-inferiority margin was 12·5%. This trial is registered with ClinicalTrials.gov, number NCT02847026.

FINDINGS

Between Sept 1, 2016 and May 2, 2017, 1076 participants were randomly assigned and included in the modified intention-to-treat analysis: 271 in Group A, 267 in group B, 268 in group C, and 270 in group D. Vaccine response at 22 weeks to two doses of fIPV (group D) was significantly higher (p<0·0001) than to one dose of IPV (groups A and B) for all three poliovirus serotypes: the type 1 response comprised 212 (79% [95% CI 73-83]) versus 305 (57% [53-61]) participants, the type 2 response comprised 173 (64% [58-70]) versus 249 (46% [42-51]) participants, and the type 3 response comprised 196 (73% [67-78]) versus 196 (36% [33-41]) participants. At 26 weeks, the fIPV booster was non-inferior to IPV (group B vs group A) for serotype 1 (-1·12% [90% CI -2·18 to -0·06]), serotype 2 (0·40%, [-2·22 to 1·42]), and serotype 3 (1·51% [-3·23 to -0·21]). Of 129 adverse events, 21 were classified as serious including one death; none were attributed to IPV or fIPV.

INTERPRETATION

fIPV appears to be an effective dose-sparing strategy for routine immunisation and outbreak responses.

FUNDING

US Centers for Disease Control and Prevention.

Herd protection of unvaccinated adults by oral cholera vaccines in rural Bangladesh

BACKGROUND

Past research has suggested that the most cost-effective approach to using oral cholera vaccines (OCVs) to control endemic cholera may be to target only children <15 y of age. However, the assumption that vaccination of children with OCVs protects unvaccinated adults has never been tested.

METHODS

We reanalyzed the data of an OCV trial in Bangladesh in which children 2-15 y of age and women >15 y of age were allocated to OCV or placebo and assessed herd protection by relating the risk of cholera in each nonvaccinated adult (>15 y) to OCV coverage (OCVC) of residents residing in virtual clusters within 500 m of the residence of that unvaccinated adult.

RESULTS

The risk of cholera in unvaccinated adults decreased by 14% with each 10% increase of OCVC of all targeted age groups (95% 7 to 21%, p=0.0004). Also, the risk of cholera in unvaccinated adults decreased by 13% with each 10% increase in OCVC of children 2-15 y of age (95% CI 6 to 20%, p=0.0007). A high correlation between levels of OCVC of children and adult females precluded an assessment of the herd protection of unvaccinated adults by vaccinating children <16 y of age, independent of concomitant vaccination of adult women.

CONCLUSIONS

Unvaccinated adults benefitted from herd protection conferred by OCVs in this trial. Vaccination of children may be sufficient to confer this protection, but this possibility needs to be evaluated in further studies.

A phase I trial of WRSS1, a Shigella sonnei live oral vaccine in Bangladeshi adults and children

Shigella sonnei live vaccine candidate, WRSS1, which was previously evaluated in US, Israeli and Thai volunteers, was administered orally to Bangladeshi adults and children to assess its safety, clinical tolerability and immunogenicity. In a randomized, placebo-controlled, dose-escalation, age-descending study, 39 adults (18-39 years) and 64 children (5-9 years) were enrolled. Each adult cohort (n = 13) received one dose of 3x10⁴, or three doses of 3 × 10⁵ or 3 × 10⁶ colony forming unit (CFU) of WRSS1 (n = 10) or placebo (n = 3). Each child cohort (n = 16) received one dose of 3x10³, or three doses of 3x10⁴, 3x10⁵, or 3 × 10⁶ CFU WRSS1 (n = 12) or placebo (n = 4). WRSS1 elicited mostly mild and transient reactogenicity events in adults and children. In the 3 × 10⁶ dose group, 50% of the adults shed the vaccine; no shedding was seen in children. At the highest dose, 100% of adults and 40% of children responded with a ≥ 4-fold increase of S. sonnei LPS-specific IgA antibody in lymphocyte supernatant (ALS). At the same dose, 63% of adults and 70% of children seroconverted with IgA to LPS, while in placebo, 33% of adults and 18% of children seroconverted. Both the vaccinees and placebos responded with fecal IgA to LPS, indicating persistent exposure to Shigella infections. In conclusion, WRSS1 was found safe up to 10⁶ CFU dose and immunogenic in adults and children in Bangladesh. These data indicate that live, oral Shigella vaccine candidates, including WRSS1 can potentially be evaluated in toddlers and infants (<2 years of age), who comprise the target population in an endemic environment.

Use of oral cholera vaccine as a vaccine probe to determine the burden of culture-negative cholera

Analyses of stool from patients with acute watery diarrhea (AWD) using sensitive molecular diagnostics have challenged whether fecal microbiological cultures have acceptably high sensitivity for cholera diagnosis. If true, these findings imply that current estimates of the global burden of cholera, which rely largely on culture-confirmation, may be underestimates. We conducted a vaccine probe study to evaluate this possibility, assessing whether an effective killed oral cholera vaccine (OCV) tested in a field trial in a cholera-endemic population conferred protection against cholera culture-negative AWD, with the assumption that if cultures are indeed insensitive, OCV protection in such cases should be detectable. We re-analysed the data of a Phase III individually-randomized placebo-controlled efficacy trial of killed OCVs conducted in Matlab, Bangladesh in 1985. We calculated the protective efficacy (PE) of a killed whole cell-only (WC-only) OCV against first-episodes of cholera culture-negative AWD during two years of post-dosing follow-up. In secondary analyses, we evaluated PE against cholera culture-negative AWD by age at vaccination, season of onset, and disease severity. In this trial 50,770 people received at least 2 complete doses of either WC-only OCV or placebo, and 791 first episodes of AWD were reported during the follow-up period, of which 365 were culture-positive for Vibrio cholerae O1. Of the 426 culture-negative AWD episodes, 215 occurred in the WC group and 211 occurred in the placebo group (adjusted PE = -1.7%; 95%CI -23.0 to 13.9%, p = 0.859). No measurable PE of OCV was observed against all or severe cholera culture-negative AWD when measured overall or by age and season subgroups. In this OCV probe study we detected no vaccine protection against AWD episodes for which fecal cultures were negative for Vibrio cholera O1. Results from this setting suggest that fecal cultures from patients with AWD were highly sensitive for cholera episodes that were etiologically attributable to this pathogen. Similar analyses of other OCV randomized controlled trials are recommended to corroborate these findings.

Conventional microbiological culture has remained a relatively uncontested ‘gold standard’ for the diagnosis of cholera; however, emerging methods, including sensitive molecular tests, challenge the current paradigm. One pivotal article demonstrated that culture failed to detect cholera in one-third of the cholera-positive stool specimens confirmed by other methods. This finding underscored the absence of a reliable reference test, further complicated by newer tests outperforming the gold standard, leaving no suitable comparator. In this study, we used oral cholera vaccine as a probe to investigate the reliability of conventional culture as a diagnostic for cholera by measuring the effectiveness of the vaccine against cholera culture-negative acute watery diarrhea. We did not find any evidence of protection, implying that the culture diagnostics used were reliable. The dynamics of cholera transmission require a rapid response, and ascertaining the best rapid diagnostic test for early detection of outbreaks will maximize the effectiveness of chronically limited resources in high risk regions. As techniques advance, well-designed studies should be implemented to systematically evaluate their merit against established methods, and improved diagnostics, including rapid diagnostics and microbiological culture, should be implemented into cholera control programs to reduce cholera transmission by creating a better trigger for outbreak response.

Abstract P4-14-01: Estrogen levels in premenopausal patients (pts) with hormone-receptor positive (HR+) early breast cancer (BC) receiving adjuvant triptorelin (Trip) plus exemestane (E) or tamoxifen (T) in the SOFT trial: SOFT-EST substudy final analysis

Background: Optimal endocrine therapy for premenopausal pts with early HR+ BC may depend on complete estrogen suppression with GnRH analog, which is crucial when using concurrent aromatase inhibitors (AIs). SOFT-EST is a prospective substudy of the phase 3 SOFT trial aiming to describe estradiol (E2), estrone (E1) and estrone sulphate (E1S) during the first 4 years (y) of monthly Trip+E/T and to assess if there were suboptimally estrogen suppressed (SES) pts in the E+Trip group. Secondary objectives included associations of baseline (BL) factors with SES, early SES with later SES, and SES with disease-free survival (DFS; exploratory objective).

Methods: Patients from select centers who consented and enrolled in SOFT, selected Trip as ovarian function suppression method, and were randomized to E+Trip or T+Trip were eligible for SOFT-EST until the accrual goal (120 pts: 90 E+Trip; 30 T+Trip). Prem status for SOFT eligibility was based on local E2. Blood sampling timepoints were 0, 3, 6, 12, 18, 24, 36 & 48 months (m) until Trip stopped. Serum estrogens were measured centrally by high specificity/sensitivity GC/MSMS and were not available during the study. For 4y analyses, SES was defined as E2 levels &gt;2.72 pg/mL in ≥2 post-BL samples (E2 levels not consistent with postmenopausal (PM) status on AIs [Smith IE, JCO 2006]), or vaginal bleeding &gt;3m after Trip start, or pregnancy. We explored 2 additional cutoffs: &gt;10 pg/mL (clearly inconsistent with PM status on AIs) and &gt;20 pg/mL (inconsistent with GnRH analog-related PM status). The analysis is intention-to-treat based on E/T assignment; as-treated analyses are forthcoming.

Results: From Mar 2009 to Jan 2011,109 pts (E/T=83/26) started Trip and had ≥2 samples drawn. In pts assigned E+Trip, median reductions from BL in E1, E2 and E1S were &gt;95% at all timepoints and significantly lower than in T+Trip. Post-BL E2 geometric mean ranged 0.8-1.3 pg/mL in E+Trip and 16.5-18.3 pg/mL in T+Trip. 21 (25%), 11 (13%) and 6 (7%) pts assigned to E+Trip had E2&gt;2.72, &gt;10, and &gt;20 pg/mL in ≥2 post BL samples or vaginal bleeding (n=3), respectively. Early SES [(≥1 E2 value &gt;2.72 pg/mL or vaginal bleeding in the firsty] predicted later SES [≥1 E2 value &gt;2.72 or vaginal bleeding thereafter (n=1); p&lt;0.001]. BL factors related to SES were higher E2, lower FSH and lower LH values (p=0.02, p&lt;0.01, p&lt;0.01 respectively). 12m FSH levels were not related to SES. In pts assigned E+Trip, after 6y median follow-up, DFS events were seen in 0 of 21 pts with SES vs 5 of 62 pts without SES.

Conclusions: Most pts on E+Trip had a profound E2 drop consistent with postmenopausal status on AI, but &gt;20% assigned to E+Trip had ≥2 E2 values &gt;2.72 pg/mL and 4% had vaginal bleeding, with those having higher E2, lower FSH/LH at BL being at higher risk. SES at 12m predicted subsequent SES. Few DFS events limit the ability to assess clinical relevance of SES with disease outcomes.

BL characteristicsN-109Prior chemo60 (55%)Amenorrhea39 (36%)Age &lt;35y8 (7%) Median (range)Age, y44 (25-53)BMI, kg/m224 (22-28)Estrogen (pg/mL) E252 (7-119)E141 (24-70)E1S894 (304-1320)FSH/LH (IU/L) FSH15 (7-47)LH11 (6-26)

Citation Format: Bellet M, Gray K, Francis P, Láng I, Ciruelos E, Lluch A, Ángel Climent M, Catalán G, Avella A, Bohn U, González-Martin A, Zaman K, Ferrer R, Azaro A, Rajasekaran A, De la Peña L, Fleming G, Regan MM. Estrogen levels in premenopausal patients (pts) with hormone-receptor positive (HR+) early breast cancer (BC) receiving adjuvant triptorelin (Trip) plus exemestane (E) or tamoxifen (T) in the SOFT trial: SOFT-EST substudy final analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-01.

Abstract P1-18-01: Incidence of hypocalcemia in patients with metastatic breast cancer under treatment with denosumab: A non-inferiority phase III trial assessing prevention of symptomatic skeletal events (SSE) with denosumab administered every 4 weeks versus every 12 weeks: SAKK 96/12 (REDUSE)

Background

Monthly Denosumab (DN) has shown superiority over zoledronic acid (ZA) in delaying skeletal related events. Randomized trials have shown that ZA given every 12 weeks (q12w) is non-inferior to ZA given every 4 weeks (q4w). The primary endpoint of the REDUSE-trial is non-inferiority for SSE for DN q12w versus q4w. Here we present early data for hypocalcemia (HC), a secondary endpoint.

Methods

Patients with bone metastasis from breast cancer (BC) not pretreated with DN or Bisphosphonates were randomized 1:1 to receive DN q4w (Arm A) versus q12w (Arm B) after a 3-month induction phase with q4w therapy for both arms. All patients received vitamin D 400 U (VitD) and calcium (Ca) 500 mg daily. Measurement of albumin-corrected serum-Ca was mandatory before each DN injection (HC defined as &lt;2.0 mmol/l like in CTCAE V4.0). This safety interim analysis was performed after 3.5 years of accrual. Patients who received at least 1 dose of DN were considered evaluable.

Results

351 BC-patients are currently included (177 in Arm A, 174 in Arm B). HC was the most common side effect with a rate of 20% in the first 16 weeks (during the induction phase with DN q4w for both Arms) and 19% afterwards (combined for Arms A and B). After week 16 HC-prevalence differed between the two arms: while HC was present in 25% in Arm A (q4w), the rate was only 12% in Arm B (q12w). Grade 3 HC (i.e. corrected Ca 1.5 - 1.74 mmol/l or hospitalisation indicated) was rare (0.3%), no grade 4 HC occurred. After 1 year of treatment, the rate of HC compared to the induction phase had decreased in Arm B but not in Arm A (A: 25%, B: 12%). Since HC improved in more patients in Arm B than in Arm A whereas it worsened in more patients in Arm A than in Arm B, a remarkable difference for HC resulted between the two arms.

Rates of hypocalcemia and change of severity after week 16* Arm A (N = 177)Arm B (N = 174)Rates of hypocalcemian (%)n (%)Patients with hypocalcemia at any time49 (28%)46 (26%)Patients with hypocalcemia after week 16*44 (25%)21 (12%)   Change in hypocalcemia grade after week 16*for the 49 patients with hypocalcemiafor the 46 patients with hypocalcemiaWorsening25 (51%)8 (17%)Stable10 (20%)9 (20%)Improving14 (29%)29 (63%)   *week 16: i.e. the time where the schedules of DN begin to differ between Arm A and Arm BArm A: DN q4w for weeks 1 - 12 and likewise thereafter / Arm B: DN q4w for weeks 1 - 12 and q12w thereafter

Conclusions

In our trial up to 20% of all BC patients treated with DN experienced HC in the q4w induction phase despite mandatory supplementation of VitD and Ca. This rate is considerably higher than the numbers reported in the registration trials of DN (where it was 5.5% for BC). After the induction phase, HC is markedly reduced in the q12w arm compared to q4w. This suggests that DN given q12w has a more favorable long-term safety profile in terms of HC compared to DN q4w.

Citation Format: Müller A, Templeton AJ, Hayoz S, Hawle H, Hasler-Strub U, Schwitter M, Pestalozzi BC, Pagani O, Bützberger P, Wehrhahn T, Rauch D, Inauen R, Betticher D, Zaman K, Bodmer A, Popescu RA, Rothschild S, Schardt J, Borner M, Fuhrer A, Schär C, Gillessen S, von Moos R, For the Swiss Group for Clinical Cancer Research (SAKK). Incidence of hypocalcemia in patients with metastatic breast cancer under treatment with denosumab: A non-inferiority phase III trial assessing prevention of symptomatic skeletal events (SSE) with denosumab administered every 4 weeks versus every 12 weeks: SAKK 96/12 (REDUSE) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-18-01.

An update from hospital-based surveillance for rotavirus gastroenteritis among young children in Bangladesh, July 2012 to June 2017

INTRODUCTION

In preparation for the introduction of a rotavirus vaccine into the routine immunization program of Bangladesh in 2018, we report data and highlight evolving genotypes from five years of active hospital-based rotavirus surveillance which began in July 2012.

METHODS

We enrolled and collected fresh stool from every fourth child < 5 years admitted with acute gastroenteritis (AGE) at 8 participating surveillance hospitals. Rotavirus infections were detected by enzyme immune assay. Twenty-five percent of rotavirus isolates were genotyped using reverse transcription polymerase chain reaction.

RESULTS

We found that 64% (4832/7562) of children < 5 years of age admitted with AGE had evidence of rotavirus infection. The majority (57%) of patients with rotavirus infection were <12 months of age. The most common strains were G1P[8] (43%), G12P[8] (15%) and G9P[8] (9%); 11% of children had mixed infection.G3P[8], which has not been reported in Bangladesh since 2001, was documented for the first time in our surveillance system.

CONCLUSIONS

The high burden of rotavirus-associated hospitalizations highlights the potential value of rotavirus vaccination in Bangladesh. Continued surveillance is important for monitoring the impact of vaccination as well as monitoring evolving genotypes.

Metastatic or locally advanced breast cancer patients: towards an expert consensus on nab-paclitaxel treatment in HER2-negative tumours-the MACBETH project

INTRODUCTION

Despite the large use of nab-paclitaxel as a treatment option in metastatic breast cancer (MBC) across different countries, no definitive data are available in particular clinical situations.

AREAS COVERED

Efficacy, safety and schedule issues concerning available literature on nab-paclitaxel in advanced breast cancer and in specific subgroups of patients have been discussed and voted during an International Expert Meeting. Ten expert specialists in oncology, with extensive clinical experience on Nab-P and publications in the field of MBC have been identified. Six scientific areas of interest have been covered, generating 13 specific Statements for Nab-P, after literature review. For efficacy issues, a summary of research quality was performed adopting the GRADE algorithm for evidence scoring. The panel members were invited to express their opinion on the statements, in case of disagreement all the controversial opinions and the relative motivations have been made public.

EXPERT OPINION

Consensus was reached in 30.8% of the Nab-P statements, mainly those regarding safety issues, whereas ones regarding efficacy and schedule still remain controversial areas, requiring further data originated by the literature.

Health seeking behaviour and delayed management of tuberculosis patients in rural Bangladesh

Background

Early diagnosis of tuberculosis (TB) and involvement of the public-private partnership are critical to eradicate TB. Patients need to receive proper treatment through the National Tuberculosis Control Programme (NTP). This study describes various predictors for health seeking behaviour of TB patients and health system delay made by the different health care providers.

Methods

A cross-sectional study was conducted in a public health facility of a rural area in Bangladesh. Newly diagnosed smear positive pulmonary TB (PTB) patients who were ≥ 15 years of age were sequentially enrolled in this study. The socio-demographic characteristics and proportion of health care utilization by the patients, and health system delay made by the health care providers were calculated. Multivariate analysis was conducted to determine the independent association of the risk factors with the time to seek medical care.

Results

Two hundred and eighty patients were enrolled in this study. Among them, 73.6% were male and 26.4% were female. A hundred percent of patients primarily sought treatment for their cough, 170 (60.7%) first consulted a non-qualified practitioner while 110 patients (39.3%) first consulted with qualified practitioners about their symptoms. Pharmacy contact was the highest (27.9%) among the non-qualified practitioners, and 58.9% non-qualified practitioners prescribed treatment without any laboratory investigation. The average health system delay was 68.5 days. Multiple logistic regressions revealed a significant difference between uneducated and educated patients (OR 2.33; CI 1.39–3.92), and qualified and non-qualified practitioners (OR 2.34; CI 1.38–3.96) to be independent predictors of health system delay.

Conclusions

Compared to men, fewer women sought TB treatment. Uneducated patients and questionably qualified practitioners made for a longer delay in detecting TB. Increasing public health awareness and improving health seeking behavior of females and uneducated patients, and greater participation of the qualified practitioners in the NTP are highly recommended.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3430-0) contains supplementary material, which is available to authorized users.