Immunogenicity of pentavalent rotavirus vaccine in Chinese infants

BackgroundA phase III, randomized, double-blind, placebo-controlled clinical study was conducted in China to assess the efficacy, safety, and immunogenicity of the pentavalent rotavirus vaccine (RotaTeq^TM, RV5) among Chinese infants. The efficacy and safety data have been previously reported. This report presents the immunogenicity data of the study.Methods4,040 infants aged 6–12 weeks were randomly assigned in a 1:1 ratio to receive 3 oral doses of RV5 or placebo. Trivalent oral poliovirus vaccine (tOPV) and diphtheria, tetanus, and acellular pertussis vaccine (DTaP) were administered in a staggered-use (N = 3,240) or concomitant-use (N = 800) schedule. Immunogenicity of RV5 was evaluated in 800 participants (400 participants from each staggered- and concomitant-use immunogenicity subgroup). Geometric mean titers (GMTs) and seroresponse rates (≥3-fold rise from baseline to PD3) were measured for anti-rotavirus IgA in the staggered- and concomitant-use subgroups and measured for serum neutralizing antibodies (SNAs) to human rotavirus serotypes G1, G2, G3, G4, P1A[8] in the staggered-use subgroup. Immune responses to tOPV and DTaP co-administered with RV5 were also evaluated in the concomitant-use immunogenicity subgroup. (ClinicalTrials.gov registry: NCT02062385)ResultsThe PD3 GMT and seroresponse rate of anti-rotavirus IgA were higher in the RV5 group (82.42 units/mL, 89.4%) compared to the placebo group (0.33 units/mL, 10.1%). Rotavirus type-specific SNA responses were also higher in the RV5 group compared to the placebo group. In the concomitant-use subgroup, the seroprotection rates of anti-poliovirus type 1, 2, 3 in the participants who received RV5 were non-inferior to those who received placebo, and the antibody responses to DTaP antigens were comparable between the two vaccination groups.ConclusionsRV5 was immunogenic in Chinese infants. Immune responses induced by tOPV and DTaP were not affected by the concomitant use of RV5.     

Detection of fecal shedding of rotavirus vaccine in infants following their first dose of pentavalent rotavirus vaccine

Studies on rotavirus vaccine shedding and its potential transmission within households including immunocompromised individuals are needed to better define the potential risks and benefits of vaccination. We examined fecal shedding of pentavalent rotavirus vaccine (RV5) for 9 days following the first dose of vaccine in infants between 6 and 12 weeks of age. Rotavirus antigen was detected by enzyme immunoassay (EIA), and vaccine-type rotavirus was identified by nucleotide sequencing based on genetic relatedness to the RV5 VP6 gene. Stool from 22 (21.4%) of 103 children contained rotavirus antigen-positive specimens on ≥1 post-vaccination days. Rotavirus antigen was detected as early as post-vaccination day 3 and as late as day 9, with peak numbers of shedding on post-vaccination days 6 through 8. Vaccine-type rotavirus was detected in all 50 antigen-positive specimens and 8 of 8 antigen-negative specimens. Nine (75%) of 12 EIA-positive and 1 EIA-negative samples tested culture-positive for vaccine-type rotavirus. Fecal shedding of rotavirus vaccine virus after the first dose of RV5 occurred over a wide range of post-vaccination days not previously studied. These findings will help better define the potential for horizontal transmission of vaccine virus among immunocompromised household contacts of vaccinated infants for future studies.     

Efficacy of the oral pentavalent rotavirus vaccine in Mali

The oral, pentavalent rotavirus vaccine (PRV), RotaTeq was assessed for prevention of severe rotavirus gastroenteritis (RVGE) in young children in two multi-site, randomized, placebo-controlled field trials; one in Asia (Vietnam and Bangladesh) and the other in sub-Saharan Africa (Ghana, Kenya and Mali). The efficacy results for the Mali site of the multi-country trial are presented here. We randomly assigned infants in a 1:1 ratio to receive 3 doses of PRV/placebo at approximately 6, 10, and 14 weeks of age. Gastroenteritis episodes were captured passively at the local health centers and by home visits. The primary study outcome was severe RVGE, as defined by a score of ≥ 11 using the Vesikari Clinical Scoring System occurring ≥ 14 days after the third dose until the end of the study. Other efficacy analyses included efficacy against severe RVGE through the first year and during the second years of life, as well as efficacy after receiving at least one dose of vaccine. In total, 1960 infants were enrolled in the trial at the Mali site and sera were collected on a subset of infants (approximately 150) for immunogenicity testing. In the first year of follow-up, largely due to cultural practices to visit traditional healers as the first point of care, the point estimate of efficacy was unreliable: the per protocol vaccine efficacy against severe RVGE was 1% (95% confidence interval [CI]: -431.7, 81.6); the intention-to-treat vaccine efficacy was 42.9% (95% CI: -125.7, 87.7). During the second year of follow-up, after the surveillance system was modified to adapt to local customs and health care seeking practices, the point estimate of per-protocol vaccine efficacy was 19.2% (95% CI: -23.1,47.3%). 82.5% of Malian infants (95% CI: 70.1,91.3%) who received PRV mounted a seroresponse (≥ 3-fold rise from baseline (prevaccination) to post-dose 3 vaccination) of anti-rotavirus immunoglobulin A antibody, with a post third-dose geometric mean titer (GMT) of 31.3 units/mL. By contrast, only 20.0% of placebo recipients (95% CI: 10.0, 33.7%) developed a seroresponse and the post-third dose GMT was 3.2 units/mL. None of the serious clinical adverse events observed were considered to be vaccine-related.     

RotaTeq,a pentavalent rotavirus vaccine: Efficacy and safety among infants in Europe

A pentavalent human–bovine reassortant oral rotavirus vaccine, RotaTeq^®, was evaluated among nearly 70,000 infants in the Rotavirus Efficacy and Safety Trial (REST), of which 30,523 were from Europe. All infants were followed for serious adverse events as well as hospitalizations and emergency department (ED) visits. All adverse events, health care utilization, and RVGE regardless of severity were evaluated in the clinical efficacy cohort (N = 2686) in Finland. RotaTeq^® was 98.3% (95% CI, 90.2–100%) and 68.0% (95% CI 60.3–74.4%) efficacious against severe rotavirus gastroenteritis (RVGE) and all RVGE due to any serotype for two rotavirus seasons post-vaccination. The combined rate of hospitalizations and ED visits due to RVGE of any serotype was reduced by 94.5% (95% CI, 91.3–96.8%) for up to 2 years after vaccination. There were no statistically significant differences between RotaTeq^® and placebo for any of the safety outcomes. In Europe, RotaTeq^® was highly efficacious and well tolerated.     

Immunogenicity and lot-to-lot consistency of a ready to use liquid bovine-human reassortant pentavalent rotavirus vaccine (ROTASIIL - Liquid) in Indian infants

Background

A lyophilized bovine-human rotavirus reassortant pentavalent vaccine (BRV-PV, Rotasiil®) was licensed in 2016. A liquid formulation of this vaccine (LBRV-PV, Rotasiil - Liquid) was subsequently developed and was tested for non-inferiority to Rotasiil® and for lot-to-lot consistency.

Impact of pentavalent rotavirus vaccine against severe rotavirus diarrhoea in The Gambia

IntroductionRotavirus vaccines protect against the leading cause of severe childhood diarrhoea, and have been introduced in many low-income African countries. The Gambia introducedRotateq® (RV5) into their national immunization program in 2013. We revieweddata from an active rotavirus sentinel surveillancesitefor early evidence of vaccine impact.MethodsWe compared rotavirus prevalence in diarrhoeal stool in children< 5 years of age admittedat the Edward Francis Small Teaching Hospital sentinel surveillance site before (2013) andafterRV5 introduction (2015–2016) in the Gambia. The rotavirus-percent positive was separately compared for all diarrhoealhospitalizations and for hospitalizations with severe symptoms. Rotavirus prevalence was compared annually for the pre-vaccine year of 2013 with post-vaccine years of 2015 and 2016 using chi-square or Fisher’s exact tests and the p-value to establish significant relationship was set at p < 0.05. All analyses were completed in SAS 9.3 (SAS Analytics, North Carolina).ResultsRotavirus prevalence among all diarrhoeahospitalizations decreased from 22% in 2013 to 11% in 2015 (p = 0.04), while remaining unchanged in 2016 (18%, p = 0.56). For hospitalizations that were clinically severe and/or treated with intravenous fluids (mean of 46 per year), the rotavirus prevalence decreased from 33% in 2013 to 8% in 2015 (p = 0.04), and to 15% in 2016 (p = 0.08). The children with age <1 year accounted for 45% the population infected with rotavirus in both pre and post rotavirus vaccination periods.ConclusionsRotavirus vaccine introduction in the Gambia could be among factors resulting in decreased diarrhea hospitalizations among children at the Edward Francis Small Teaching Hospital, particularly those with severe disease. These results support the continuation of rotavirus vaccine and additional monitoring of rotavirus hospitalization trends in the country.     

Secondary efficacy endpoints of the pentavalent rotavirus vaccine against gastroenteritis in sub-Saharan Africa

The efficacy of the pentavalent rotavirus vaccine (PRV), RotaTeq(?), was evaluated in a double-blind, placebo-controlled, multicenter Phase III clinical trial conducted (April 2007-March 2009) in 3 low-income countries in Africa: Ghana, Kenya, and Mali. In total, 5468 infants were randomized 1:1 to receive 3 doses of PRV/placebo at approximately 6, 10, and 14 weeks of age; concomitant administration with routine EPI vaccines, including OPV, was allowed. HIV-infected infants were not excluded. The primary endpoint, vaccine efficacy (VE) against severe-rotavirus gastroenteritis (RVGE), as measured by Vesikari scoring system (VSS, score ≥11), from ≥14 days following Dose 3 through a follow-up period of nearly 2 years in the combined 3 African countries, and secondary endpoints by total follow-up period have been previously reported. In this study, we report post hoc subgroup analyses on secondary endpoints of public health importance. VE against RVGE of any severity was 49.2% (95%CI: 29.9, 63.5) through the first year of life and 30.5% (95%CI: 16.7, 42.2) through the complete follow-up period. VE against severe-gastroenteritis of any etiology was 21.5% (95%CI: <0, 38.4) through the first year of life and 10.6% (95%CI: <0, 24.9) through the complete follow-up period. Through the complete follow-up period, VE against severe-RVGE caused by (i) vaccine-contained G and P types (G1-G4, P1A[8]), (ii) non-vaccine G types (G8, G9, G10), and (iii) non-vaccine P types (P1B[4], P2A[6]) was 34.0% (95%CI:11.2, 51.2), 81.8% (95%CI:16.5, 98.0) and 40.7% (95%CI:8.4, 62.1), respectively. There was a trend towards higher VE with higher disease severity, although in some cases the numbers were small. In African countries with high under-5 mortality rates, PRV significantly reduced RVGE through nearly 2 years of follow-up; more modest reductions were observed against gastroenteritis of any etiology. PRV provides protection against severe-RVGE caused by diverse rotavirus genotypes, including those not contained in the vaccine.     

A randomized Phase III clinical trial to assess the efficacy of a bovine-human reassortant pentavalent rotavirus vaccine in Indian infants

Rotavirus is the most common cause of moderate-to-severe infant diarrhoea in developing countries, resulting in enormous morbidity, mortality, and economic burden. A bovine-human reassortant pentavalent rotavirus vaccine (BRV-PV) targeting the globally most common strains was developed in India and tested in a randomized, double-blind, placebo-controlled end-point driven Phase III efficacy clinical trial implemented at six sites across India. Infants 6 to 8 weeks of age were randomized (1:1) to receive three oral doses of BRV-PV or placebo at 6, 10, and 14 weeks of age along with routine vaccines. Home visit surveillance was conducted to detect severe rotavirus gastroenteritis (SRVGE) and safety outcomes until the children reached two years of age. A total of 3749 infants received BRV-PV while 3751 received placebo. At the time of the primary end-point (when the minimum number of cases needed for analysis were accrued) the vaccine efficacy against SRVGE was 36% (95% CI 11.7, 53.6, p = 0.0067) in the per protocol (PP) analysis, and 41.9% (95% CI 21.1, 57.3, p = 0.0005) in the intent to treat (ITT) analysis. Vaccine efficacy over the entire follow-up period (until children reached two years of age) was 39.5% (95% CI 26.7, 50, p < 0.0001) in the PP analysis and 38.8% (95% CI, 26.4, 49, p < 0.0001) in the ITT analysis. Vaccine efficacy against the very severe rotavirus cases (VSRVGE, Vesikari score ≥ 16) was 60.5% (95% CI 17.7, 81, p = 0.0131) at the time of the primary analysis and 54.7% (95% CI 29.7, 70.8, p = 0.0004) for the complete follow-period in the PP population. The incidence of solicited, unsolicited, and serious adverse events were similar in both the vaccine and placebo groups. Likewise, the number of intussusceptions and deaths were similar between both groups. Thus, BRV-PV is an effective, well tolerated and safe vaccine in Indian infants. (Trial registration: Clinical Trials.Gov [NCT 02133690] and Clinical Trial Registry of India [CTRI/2013/05/003667]).     

Catching-up with pentavalent vaccine: Exploring reasons behind lower rotavirus vaccine coverage in El Salvador

Rotavirus vaccine was introduced in El Salvador in 2006 and is recommended to be given concomitantly with DTP–HepB–Haemophilus influenzae type b (pentavalent) vaccine at ages 2 months (upper age limit 15 weeks) and 4 months (upper age limit 8 months) of age. However, rotavirus vaccination coverage continues to lag behind that of pentavalent vaccine, even in years when national rotavirus vaccine stock-outs have not occurred. We analyzed factors associated with receipt of oral rotavirus vaccine among children who received at least 2 doses of pentavalent vaccine in a stratified cluster survey of children aged 24–59 months conducted in El Salvador in 2011. Vaccine doses included were documented on vaccination cards (94.4%) or in health facility records (5.6%). Logistic regression and survival analysis were used to assess factors associated with vaccination status and age at vaccination. Receipt of pentavalent vaccine by age 15 weeks was associated with rotavirus vaccination (OR: 5.1; 95% CI 2.7, 9.4), and receipt of the second pentavalent dose by age 32 weeks was associated with receipt of two rotavirus vaccine doses (OR: 5.0; 95% CI 2.1–12.3). Timely coverage with the first pentavalent vaccine dose was 88.2% in the 2007 cohort and 91.1% in the 2008 cohort (p = 0.04). Children born in 2009, when a four-month national rotavirus vaccine stock-out occurred, had an older median age of receipt of rotavirus vaccine and were less likely to receive rotavirus on the same date as the same dose of pentavalent vaccine than children born in 2007 and 2008. Upper age limit recommendations for rotavirus vaccine administration contributed to suboptimal vaccination coverage. Survey data suggest that late rotavirus vaccination and co-administration with later doses of pentavalent vaccine among children born in 2009 helped increase rotavirus vaccine coverage following shortages.     

Evaluation of cost-effectiveness of live oral pentavalent reassortant rotavirus vaccine introduction in Ghana

Background

Globally, rotavirus gastroenteritis is the most common identifiable cause of severe diarrhea in children under 5. Recently introduced rotavirus vaccines from Merck &; Co. and GlaxoSmithKline have the potential to save hundreds of thousands of lives. Efficacy results in Ghana suggest Merck &; Co.’s live oral pentavalent rotavirus vaccine (RotaTeq^®) prevents 65.0% of severe gastroenteritis due to rotavirus infection in children under 5. The announcement by Merck and GSK to make their rotavirus vaccines available for developing nations at reduced prices provides Ghana with the opportunity to introduce rotavirus vaccines into the national immunization program after investigation of the medical, economic and political implications.

Methods

We estimated the average costs of treating children with diarrhea in the Ashanti region of Ghana as inpatients and outpatients. Using these results, data from rotavirus surveillance studies, and recent rotavirus vaccine efficacy evaluation, we estimated the cost-effectiveness of introducing RotaTeq in Ghana.

Results

Based on our prospective calculations, we estimated an average inpatient and outpatient costs of $233.97 and $17.09, respectively, for treating childhood diarrhea. Using the 2003 birth cohort, RotaTeq introduction could save 1554 lives and avert 93,109 disability-adjusted life-years (DALYs) annually. At a market price of $5 per dose, introducing RotaTeq would have a base-case cost of $62.26 per DALY averted, at a market price of $3.50 per dose, a base-case cost of $39.59 per DALY averted and at market cost of $1 per dose, a base-case cost of $1.81 per DALY averted. All three values are below the 2009 Ghana per capita GDP. Thus, RotaTeq introduction into Ghana will be very cost-effective. Sensitivity analyses suggest these results are robust.

Conclusions

RotaTeq vaccination for children under five in Ghana would be a highly cost-effective public health intervention. Ghanaian health officials should seek GAVI funding and evaluate how to maximize RotaTeq access.     

Methodology and lessons-learned from the efficacy clinical trial of the pentavalent rotavirus vaccine in Bangladesh

An efficacy clinical trial with pentavalent rotavirus vaccine (PRV), RotaTeq(?), was conducted at Matlab field site of ICDDR,B, Bangladesh from March 2007 to March 2009. The methodology, including operation logistics, and lessons-learned are described in this report. Vaccination was organized at 41 fixed-site clinics twice/month. A total of 1136 infants were randomized 1:1 to receive 3 doses of PRV/placebo at approximately 6-, 10-, and 14-weeks of age with routine vaccines of the Expanded Programme on Immunization (EPI) schedule. Twelve field-workers routinely visited study participants for safety and efficacy follow-up. The study was conducted following good clinical practices and maintaining cold-chain requirements. There were no temperature deviations of clinical vaccine supplies. Data entry was done using the source documents to a central database developed by the sponsor which was linked to web. Among enrolled infants, 1128 (99.3%) received 3 doses of PRV/placebo and efficacy follow-up was conducted for a median of 554 days. For the evaluation of immunogenicity, blood samples were collected from 150 participants predose 1 and from 147 (98%) of the same participants post dose 3. Stool samples were collected from 778 (99.9%) acute gastroenteritis episodes among children who reported to diarrhoea treatment centres. Thirty-nine serious adverse events, including 6 deaths, occurred among study participants. The efficacy of PRV against severe rotavirus gastroenteritis was 42.7% through the entire follow-up period; serum anti-rotavirus IgA response was 78.1%. Inclement weather, difficult transportation, and movement of study participants were some of the challenges identified. This is the first vaccine trial in rural Bangladesh with online data entry. The study was well accepted in the community and was completed successfully.     

Determining the effectiveness of the pentavalent rotavirus vaccine against rotavirus hospitalizations and emergency department visits using two study designs

The objective of this study is to determine the vaccine effectiveness (VE) of the pentavalent rotavirus vaccine (RV5) for preventing rotavirus-related hospitalizations and emergency department (ED) visits during the 2006–07 and 2007–08 rotavirus seasons using two study designs. Active, prospective population-based surveillance was conducted to identify cases of laboratory-confirmed rotavirus-related hospitalizations and ED visits to be used in case-cohort and case-control designs. VE was calculated using one comparison group for the case-cohort method and two comparison groups for the case-control method. The VE estimates produced by the three analyses were similar. Three doses of RV5 were effective for preventing rotavirus-related hospitalizations and ED visits in each analysis, with VE estimated as 92% in all three analyses. Two doses of RV5 were also effective, with VE ranging from 79% to 83%. A single dose was effective in the case-cohort analysis, but was not significant in either of the case-control analyses. The case-cohort and the case-control study designs produced the same VE point estimates for completion of the three dose series. Two and three doses of RV5 were effective in preventing rotavirus-related hospitalizations and ED visits.     

Immunogenicity, reactogenicity and safety of the human rotavirus vaccine RIX4414 oral suspension (liquid formulation) in Finnish infants

The lyophilized formulation of a human rotavirus vaccine, Rotarix™ (RIX4414) is highly immunogenic. In order to comply with the World Health Organization's (WHO) recommendation, a liquid formulation of the vaccine that does not require reconstitution was developed. The immunogenicity, reactogenicity and safety of the liquid formulation were compared with lyophilized formulation in two Finnish studies.In Study A infants aged 6-12 weeks received two doses of the lyophilized or liquid formulation of the vaccine or placebo following a 0,1 month schedule. In Study B, infants aged 10-17 weeks received two doses of either liquid or lyophilized formulation of the vaccine. In both studies, anti-rotavirus IgA antibodies were assessed pre-vaccination and one month post-Dose 2. In Study A, the anti-rotavirus seroconversion rate was 90% (95% CI: 81.2-95.6%) and 83.7% (95% CI: 74.2-90.8%) in the groups that received the liquid and the lyophilized formulation of RIX4414, respectively; the respective anti-rotavirus IgA seroconversion rates in Study B were 88.6% (95% CI: 86.1-90.8%) and 90.5% (95% CI: 86.2-93.8%). Reactogenicity and safety profiles of the two vaccine formulations were similar.Liquid formulation of the rotavirus vaccine allows greater flexibility in supply and reduces logistical costs.     

Immunogenicity and safety of measles vaccine in ill African children

A concurrent prospective study was conducted in Rwanda to compare the immunogenicity and safety of live, attenuated measles vaccine in ill and well children. Five hundred and eighteen children aged 8 to 19 months were selected from children attending the acute care and immunization services of two clinics. Two hundred and sixty-seven ill children and 251 well children were enrolled and examined. Serological tests were performed on blood samples obtained before and 40 days after measles immunization. Among the 208 ill children and 215 well children who were seronegative at baseline and had unequivocal follow-up serological results, seroconversion rates were 81% and 80%, respectively. Side effects were modest and were equally frequent in the two study groups (15.4% among ill children versus 15.1% among well children). These results support a change in measles immunization policy in developing countries with respect to immunization of children with acute illnesses. Such a change would make a great contribution to decreasing the enormous burden of measles in the developing world through increased immunization coverage.     

Use of an immunization information system to assess the effectiveness of pentavalent rotavirus vaccine in US children

Immunization information systems (IISs) are accessible sources of immunization data. We validated immunization information from a local IIS against provider records and assessed the system's utility in evaluating vaccine effectiveness against rotavirus disease using a case-control study. Among the 91% of case and control patients with immunization records, 49% were in the IIS, and 97% had a provider record. Good agreement was observed across record sources (к = 0.65). Vaccine effectiveness (VE) was 82% using IIS data compared to 82–88% using provider data. Controls identified through the IIS provided VE estimates similar to hospital control patients. IISs could represent a valuable source of data for effectiveness evaluations.     

Safety and tolerability of a liquid bovine rotavirus pentavalent vaccine (LBRV-PV) in adults

BackgroundRotavirus Gastroenteritis (RVGE) is an important global public health problem. Recently a Lyophilized Pentavalent Human Bovine Reassortant Rotavirus vaccine (BRV-PV, Rotasiil) was licensed in India. A Liquid formulation of the same vaccine (LBRV-PV) was tested in a Phase I clinical trial.MethodsTotal 20 healthy adults were given a single oral dose of LBRV-PV and were followed for one month for safety outcomes: immediate reactions, solicited reactions, unsolicited adverse events and serious adverse events.ResultsAll 20 adults completed the study without any major protocol deviations. No immediate reaction, solicited reactions and unsolicited adverse events were reported during the study. No clinically significant changes were seen in the vital parameters and safety laboratory test results.ConclusionsLBRV-PV developed in India was safe and well tolerated in adults. Further clinical development of this vaccine in infants should be undertaken.Trial Registration – CTRI/2015/11/006,384.