T. Christopher Mast

International epidemiology of human pre-existing adenovirus (Ad) type-5, type-6, type-26 and type-36 neutralizing antibodies: Correlates of high Ad5 titers and implications for potential HIV vaccine trials

Replication-defective adenoviruses have been utilized as candidate HIV vaccine vectors. Few studies have described the international epidemiology of pre-existing immunity to adenoviruses. We enrolled 1904 participants in a cross-sectional serological survey at seven sites in Africa, Brazil, and Thailand to assess neutralizing antibodies (NA) for adenovirus types Ad5, Ad6, Ad26 and Ad36. Clinical trial samples were used to assess NA titers from the US and Europe. The proportions of participants that were negative were 14.8% (Ad5), 31.5% (Ad6); 41.2% (Ad26) and 53.6% (Ad36). Adenovirus NA titers varied by geographic location and were higher in non-US and non-European settings, especially Thailand. In multivariate logistic regression analysis, geographic setting (non-US and non-European settings) was statistically significantly associated with having higher Ad5 titers; participants from Thailand had the highest odds of having high Ad5 titers (adjusted OR=3.53, 95% CI: 2.24, 5.57). Regardless of location, titers of Ad5NA were the highest and Ad36 NA were the lowest. Coincident Ad5/6 titers were lower than either Ad5 or Ad6 titers alone. Understanding pre-existing immunity to candidate vaccine vectors may contribute to the evaluation of vaccines in international populations.

Declining pertussis incidence in Sweden following the introduction of acellular pertussis vaccine

Acellular pertussis vaccines were introduced nation-wide in Sweden in 1996, 17 years after the withdrawal of whole-cell pertussis vaccine from the childhood immunisation schedule. We report national data on age specific incidence of culture-confirmed Bordetella pertussis for 1986-2000, and clinical follow-up for 3 years (October 1997-September 2000) in children born in 1996-2000 and from children born in 1993-1994 who had participated in a trial of pertussis vaccines. The annual incidence of culture-confirmed B. pertussis was 89-150 per 100,000 before introduction of acellular pertussis vaccines and has dropped to 17-26 per 100,000. The data suggest that unimmunised infants and children who have received only one dose of pertussis vaccine were provided some protection. The decline is most obvious from the second dose onwards and remained stable for 4-5 years after the third dose in the absence of any booster dose. The first signs of waning immunity were observed at 6-7 years of age in the trial cohort. The short-term benefits reflect high vaccination coverage and high initial efficacy. The full impact of the acellular pertussis vaccination programme in infants remains to be established.

Epidemiological Profile of Rotavirus Infection in the Republic of Korea: Results from Prospective Surveillance in the Jeongeub District, 1 July 2002 through 30 June 2004

To facilitate future decisions regarding the usefulness of rotavirus vaccines in the Republic of Korea, active surveillance was conducted in a network of clinics, emergency departments, and hospitals serving Jeongeub District, Korea. Children with diarrhea underwent standard clinical evaluations, and stool specimens were collected to test for the presence of rotavirus. Parents were interviewed to collect demographic and family information. From 1 July 2002 through 30 June 2004, a total of 4106 children, representing 1 (50%) of every 2 children <5 years old in the study population, were evaluated for rotavirus diarrhea. Of the 2232 stool specimens obtained throughout the year, 460 (20.6%) were rotavirus positive; however, the monthly prevalence of rotavirus infection peaked at 49.5% in February 2004. Of the 460 rotavirus-positive stool specimens, 366 were obtained from children who visited outpatient clinics, and 94 were obtained from children who were hospitalized. By extrapolating the proportion of rotavirus-positive patients to all children with diarrhea in the surveillance system, we calculate that 882 children in Jeongeub District had rotavirus infection (which would predict that there would be 702 associated clinic visits and 180 hospitalizations). Genotyping of rotavirus strains showed that 39% of strains were type G9P[8], 24% were type G1P[8], 17% were type G3P[8], and 13% were type G2P[4]. The incidence of rotavirus diarrhea peaked at age 13-24 months, and 94% of cases occurred during the first 3 years of life. The annual incidence of all rotavirus disease-associated outcomes was 56.9 cases/1000 children <5 years old (95% confidence interval [CI], 51.9-62.2 cases/1000 children <5 years old). The incidence of rotavirus disease-associated hospitalizations was 11.6 cases/1000 children <5 years old (95% CI, 9.5-14.2 cases/1000 children <5 years old). In Korea, diarrhea is common during childhood, and the incidence of diarrhea due to rotavirus infection suggests that improved programs for the prevention and control of both rotavirus diarrhea and diarrhea due to other causes are needed.

Summary of effectiveness and impact of rotavirus vaccination with the oral pentavalent rotavirus vaccine: a systematic review of the experience in industrialized countries.

The pentavalent rotavirus (RV) vaccine RotaTeq™ has been available in industrialized countries since 2006. Several studies have been conducted to evaluate the benefit of RV vaccination under routine conditions of use. A systematic review of all publicly available data from RotaTeq™ vaccine-effectiveness and vaccination-impact studies in the USA, Europe and Australia between 2006 and February 2010 was undertaken. Depending on the population studied, effectiveness of up to 100% (95% confidence interval 85–100%) associated with decreased hospitalizations for RV gastroenteritis (RVGE) was seen. Vaccination-impact studies demonstrated that the burden of RVGE has been reduced significantly since the introduction of RV vaccination. Evidence included reductions in healthcare utilization due to RVGE (hospitalizations and emergency-department visits reduced by up to 90%), reductions in the magnitude and duration of the RV season as assessed by laboratory testing for RV, and the possible induction of herd immunity.

The impact of rotavirus gastroenteritis on the family.

BackgroundRotavirus is the leading cause of severe diarrhea in young children and causes substantial morbidity and mortality. Although the clinical aspects have been well described, little information is available regarding the emotional, social, and economic impact of rotavirus gastroenteritis on the family of a sick child. The objectives of this study were to: 1) assess the family impact of rotavirus gastroenteritis through qualitative interviews with parents; 2) compare the clinical severity of rotavirus-positive and negative gastroenteritis; 3) test a questionnaire asking parents to rank the importance of various factors associated with a case of rotavirus gastroenteritis.MethodsThe study enrolled parents and children (2–36 months of age) brought to one of the study sites (outpatient clinic or ER) if the child experienced ≥ 3 watery or looser-than normal stools and/or forceful vomiting within any 24-hour period within the prior 3 days. The clinical severity of each childs illness was rated using a clinical scoring system and stool samples were tested for rotavirus antigen. Parents of rotavirus-positive children were invited to participate in focus group or individual interviews and subsequently completed a questionnaire regarding the impact of their childs illness.ResultsOf 62 enrolled children, 43 stool samples were collected and 63% tested positive for rotavirus. Illness was more severe in children with rotavirus-positive compared to rotavirus-negative gastroenteritis (92% vs. 37.5% rated as moderate/severe). Seventeen parents of rotavirus-positive children participated in the interviews and completed the written questionnaire. Parents were frightened by the severity of vomiting and diarrhea associated with rotavirus gastroenteritis, and noted that family life was impacted in several ways including loss of sleep, missed work, and an inability to complete normal household tasks. They expressed frustration at the lack of a specific medication and the difficulty of treating the illness with oral rehydration solutions, but had a largely positive outlook concerning the prospect of a rotavirus vaccine.ConclusionA better understanding of how rotavirus gastroenteritis impacts the family can help healthcare providers ease parental fears and advise them on the characteristics of this illness, practices to prevent infection, and the optimal care of an affected child.

Cytomegalovirus viral load and mortality after haemopoietic stem cell transplantation in the era of pre-emptive therapy: a retrospective cohort study

Summary Background While CMV viral load (CMV-VL) is commonly used to guide preemptive therapy in the post-transplant setting, there is little data correlating viremia with clinical endpoints. We therefore investigated the association of CMV-VL with mortality in the first year after hematopoietic cell transplantation (HCT). Methods This cohort study included patients who received an allogeneic HCT between 01 January 2007 and 28 February 2013, were CMV seropositive or had a seropositive donor, and underwent weekly plasma CMV monitoring by PCR through day 100 post-transplant. Cox proportional hazards models were used to estimate the association of CMV-VL at different thresholds with overall by 1 year post-transplant, adjusting for the use of preemptive therapy and other factors such as neutropenia, and graft-versus-host disease. Secondary endpoints were non-relapse mortality and CMV end organ disease by 1 year post-transplant. Findings Among 926 patients, the cumulative overall mortality was 30·0% (95% CI 26·9–33·0) by 1 year. CMV-VL of ≥250 IU/ml was associated with increased risk of early (day 0–60 post-transplant) death (adjusted HR 18·1, 95% CI 8·8–37·4). The risk was attenuated after day 60 (adjusted HR 1·8, 95% CI 1·4–2·4). Similar associations were observed for higher CMV-VL thresholds. CMV-VL was also associated with increased risk of non-relapse mortality and demonstrated a dose-response relationship. The adjusted HR (95% CI) for CMV-VL of any positive CMV-VL below 500, 501–1000, and >1000 IU/ml were 1·4 (0·9–2·1), 2·6 (1·3–4·9), and 5·0 (3·1–8·1), respectively. Interpretation CMV viremia is associated with increased risk of overall and non-relapse mortality in the first year after HCT, independent of the use of preemptive therapy and with evidence of a postitive dose-response relationship. These data establish the suitability of viral load as a surrogate clinical endpoint for clinical trials for CMV vaccines, biologics, and drugs. Funding Merck & Co., Inc., National Institute of Health (K23-AI097234, K24HL093294, HL088021, CA78902, CA18029, HL122173)BACKGROUND Although cytomegalovirus viral load is commonly used to guide pre-emptive therapy in the post-transplantation setting, few data are available correlating viraemia with clinical endpoints. We therefore investigated the association between cytomegalovirus viral load and mortality in the first year after haemopoietic stem cell transplantation. METHODS In this retrospective cohort study, we included patients from the Fred Hutchinson Cancer Research Center, WA, USA, who received an allogeneic haemopoietic stem cell transplantation between Jan 1, 2007, and Feb 28, 2013, were cytomegalovirus seropositive or had a seropositive donor, and underwent weekly plasma cytomegalovirus monitoring by PCR through to day 100 post-transplantation. Cox proportional hazards models were used to estimate the association of cytomegalovirus viral load at different thresholds with overall mortality by 1 year post-transplantation, adjusting for the use of pre-emptive therapy and other factors such as neutropenia, and graft-versus-host disease. FINDINGS Of the 1037 patients initially selected for inclusion in this cohort, 87 (8%) patients were excluded because of missing cytomegalovirus testing and 24 (2%) were excluded because of their participation in cytomegalovirus prophylaxis trials. In the remaining 926 patients included in this study, the cumulative overall mortality was 30·0% (95% CI 26·9-33·0) 1 year after haemopoietic stem cell transplantation. 95 patients developed cytomegalovirus disease; death was directly attributable to cytomegalovirus disease in three (1%) of 263 patients who died in the first year after transplantation. A cytomegalovirus viral load of 250 IU/mL or greater was associated with increased risk of early (day 0-60 post-transplantation) death (adjusted hazard ratio [HR] 19·8, 95% CI 9·6-41·1). The risk was attenuated after day 60 (adjusted HR 1·8, 95% CI 1·3-2·3). Similar associations were noted for higher cytomegalovirus viral load thresholds. INTERPRETATION Cytomegalovirus viraemia is associated with an increased risk of overall mortality in the first year after haemopoietic stem cell transplantation, independent of the use of pre-emptive therapy, and with evidence of a positive dose-response relationship. These data indicate the suitability of viral load as a surrogate clinical endpoint for clinical trials for cytomegalovirus vaccines, biologics, and drugs. FUNDING Merck and Co, National Institutes of Health.

Estimates of Rotavirus Disease Burden in Hong Kong: Hospital-Based Surveillance

BACKGROUND We conducted prospective, hospital-based surveillance for rotavirus disease for a 2-year period at 4 of 12 public government (Hospital Authority [HA]) hospitals in Hong Kong. It has been estimated that HA hospitals provide 90% of inpatient care in Hong Kong. METHODS Information was collected for children <5 years old who had a primary or secondary diagnosis of diarrhea or for whom a stool sample was tested for the presence of rotavirus (by enzyme immunoassay) or bacteria (by culture). Surveillance data were compared with routine discharge information from the HAs computerized Clinical Management System (CMS). RESULTS During a 2-year period (1 April 2001 through 31 March 2003), 7391 children were admitted to the hospital with diarrhea or developed diarrhea during their hospital stay. Of these children, 5881 (80%) had a stool sample tested for the presence of rotavirus, and 30% were positive for rotavirus (representing 24% of all diarrhea-associated admissions). CMS data underreported the total percentage of diarrhea-associated admissions (15% vs. 20%) and the percentage of diarrhea-associated admissions that were the result of rotavirus infection (13% vs. 24%). Estimated rates of hospitalization for rotavirus infection (8.8 admissions/1000 children <5 years old and 18.4 admissions/1000 children <1 year old) were 4-fold higher than our previous estimates, which were determined on the basis of CMS data alone. We estimate that the cumulative risk of hospitalization with rotavirus diarrhea by age 5 years is 1 in 24. Combined active and passive (CMS) surveillance data indicate that 4.6% of all general pediatric admissions to HA hospitals in Hong Kong were associated with rotavirus infection. CONCLUSION Our study combined passive surveillance data from all Hong Kong HA hospitals with active surveillance data from 4 sentinel hospitals. The estimates of rotavirus disease burden obtained will help emphasize the effect of this important disease and create awareness of the potential for rotavirus vaccines. The surveillance model developed could also be a powerful tool for monitoring the effect of a vaccine.

Case-control study of the effectiveness of vaccination with pentavalent rotavirus vaccine in Nicaragua.

Background: In 2006, Merck & Co., Inc., partnered with the Nicaraguan Ministry of Health to demonstrate the public health impact of routine universal vaccination by delivering more than 1.3 million doses of the oral, pentavalent rotavirus vaccine (RV5) in a 3-year period. Methods: A matched case-control study evaluated the effectiveness of RV5 in reducing the risk for severe wild-type rotavirus gastroenteritis (RGE) resulting in hospitalizations and emergency department visits among children who completed the recommended 3-dose regimen as part of the routine national vaccine program. Cases were identified from 6 hospitals from February 2007 to October 2009 and were age-matched with hospital controls and community controls. Vaccine effectiveness was calculated using conditional logistic regression. Results: Three hundred RGE cases eligible for analysis were matched to 792 hospital and 851 community controls. Vaccine coverage of RV5 in the community reached 92%. Vaccine effectiveness during 2 years of follow-up against severe disease in children receiving 3 doses of RV5 was 87% (95% confidence interval [CI], 74–93) for community controls, 64% (95% CI, 44–78) for hospital controls, and 76% (95% CI, 63–84) when the groups were combined. For the combined groups, vaccine effectiveness was 85% (95% CI, 66–93) among children <12 months old at the time of RGE onset. Conclusions: The Merck-Nicaragua Rotavirus Vaccine Partnership promoted rapid and widespread uptake of a novel vaccine in a developing country. Vaccine effectiveness was greatest for children younger than 12 months of age who were at the highest risk for severe rotavirus disease.

Burden of childhood rotavirus disease on health systems in the United States: results from active surveillance before rotavirus vaccine introduction.

Background: To determine the burden of rotavirus disease before the introduction of rotavirus vaccines. Methods: From February 2005 to June 2006, prospective rotavirus surveillance was conducted in Cincinnati, Ohio, and Durham, North Carolina. Children <5 years of age presenting at hospitals and outpatient clinics with acute gastroenteritis (AGE) of <72 hours duration were enrolled. Stool samples were first tested for rotavirus by EIA and the VP7 type was determined by RT-polymerase chain reaction for rotavirus-positive samples. Medical costs were obtained from billing or accounting data. Results: A total of 1998 children were enrolled, with a mean age of 16.9 months. Among 1601 (80%) patients with a stool specimen, 44% were rotavirus positive. The rotavirus detection rate was 38% for patients admitted to hospital, 60% for patients requiring a short-stay hospital visit (<24 hour hospitalization), 49% for emergency department visits, and 37% for outpatient visits. During the rotavirus season, rotavirus accounted for 56% of all AGE cases. Only 11% of rotavirus-positive children were assigned the rotavirus-specific ICD-9-CM code and this proportion varied considerably by clinical setting. The VP7 genotypes identified were G1, 79%; G2, 14%; G3, 5%; G9, 1%; and G12, 1%. For children hospitalized with rotavirus, the estimated median direct cost was

Epidemiology and economic burden of rotavirus gastroenteritis in hospitals and paediatric clinics in Taiwan, 2005-2006.

4565, the average length of stay was 1.9 days, and parents lost 3.4 days of work. For short-stay, emergency department, and outpatient visits, the estimated median costs were