Why does the world need another rotavirus vaccine?

A “Meeting on Upstream Rotavirus Vaccines and Emerging Vaccine Producers” was held at the World Health Organization in Geneva, Switzerland on March 28–30, 2006. The purpose was to discuss, evaluate, and weigh the importance of additional rotavirus vaccine candidates following the successful international licensure of rotavirus vaccines by two major pharmaceutical companies (GlaxoSmithKline and Merck) that had been in development for many years. Both licensed vaccines are composed of live rotaviruses that are delivered orally as have been all candidate rotavirus vaccines evaluated in humans. Each is built on the experience gained with previous candidates whose development had either been discontinued or, in the case of the previously licensed rhesus rotavirus reassortant vaccine (Rotashield), was withdrawn by its manufacturer after the discovery of a rare association with intussusception. Although which alternative candidate vaccines should be supported for development and where this should be done are controversial topics, there was general agreement expressed at the Geneva meeting that further development of alternative candidates is a high priority. This development will help insure that the most safe, effective and economic vaccines are available to children in Third World nations where the vast majority of the >600,000 deaths due to rotavirus occur each year. This review is intended to provide the history and present status of rotavirus vaccines as well as a perspective on the future development of candidate vaccines as a means of promulgating plans suggested at the Geneva meeting

Identification of an immunodominant CD4+ T cell epitope in the VP6 protein of rotavirus following intranasal immunization of BALB/c mice

AbstractThe only lymphocytes required for protection against fecal rotavirus shedding after intranasal immunization of BALB/c (H-2d) mice with a chimeric rotavirus VP6 protein (MBP∷VP6) and the mucosal adjuvant LT(R192G) are CD4+ T cells. The purpose of this study was to identify CD4+ T cell epitopes within VP6 that might be responsible for this protection. To make this determination, spleen cells obtained from BALB/c mice following intranasal immunization with MBP∷VP6/LT(R192G) were stimulated in vitro with either MBP∷VP6 or overlapping VP6 peptides containing ≤30 amino acids (AA). The numbers of memory (CD44high) CD4+ T cells stimulated to produce TH1 and TH17 cytokines (IFNγ and IL-17), as well as the quantities of these cytokines released into the cell supernatants, were then measured relative to those produced in mock-stimulated cells from the same animals. One epitope expected to be found was the VP6 14-mer AA289–302, previously identified as a CD4+ T cell epitope in H-2d mice. This was not observed but instead the only VP6 epitope identified was AA242–259, the dominant CD4+ T cell epitope previously reported after oral, live rotavirus immunization

A gastrointestinal rotavirus infection mouse model for immune modulation studies

<p>Abstract</p> <p>Background</p> <p>Rotaviruses are the single most important cause of severe diarrhea in young children worldwide. The current study was conducted to assess whether colostrum containing rotavirus-specific antibodies (Gastrogard-R^®) could protect against rotavirus infection. In addition, this illness model was used to study modulatory effects of intervention on several immune parameters after re-infection.</p> <p>Methods</p> <p>BALB/c mice were treated by gavage once daily with Gastrogard-R^®from the age of 4 to 10 days, and were inoculated with rhesus rotavirus (RRV) at 7 days of age. A secondary inoculation with epizootic-diarrhea infant-mouse (EDIM) virus was administered at 17 days of age. Disease symptoms were scored daily and viral shedding was measured in fecal samples during the post-inoculation periods. Rotavirus-specific IgM, IgG and IgG subclasses in serum, T cell proliferation and rotavirus-specific delayed-type hypersensitivity (DTH) responses were also measured.</p> <p>Results</p> <p>Primary inoculation with RRV induced a mild but consistent level of diarrhea during 3-4 days post-inoculation. All mice receiving Gastrogard-R^®were 100% protected against rotavirus-induced diarrhea. Mice receiving both RRV and EDIM inoculation had a lower faecal-viral load following EDIM inoculation then mice receiving EDIM alone or Gastrogard-R^®. Mice receiving Gastrogard-R^®however displayed an enhanced rotavirus-specific T-cell proliferation whereas rotavirus-specific antibody subtypes were not affected.</p> <p>Conclusions</p> <p>Preventing RRV-induced diarrhea by Gastrogard-R^®early in life showed a diminished protection against EDIM re-infection, but a rotavirus-specific immune response was developed including both B cell and T cell responses. In general, this intervention model can be used for studying clinical symptoms as well as the immune responses required for protection against viral re-infection.</p

Impact of withholding breastfeeding at the time of vaccination on the immunogenicity of oral rotavirus vaccine--a randomized trial

Background: Breast milk contains anti-rotavirus IgA antibodies and other innate immune factors that inhibit rotavirus replication in vitro. These factors could diminish the immunogenicity of oral rotavirus vaccines, particularly if breastfeeding occurs close to the time of vaccine administration.Methods: Between April 2011 and November 2012, we conducted an open label, randomized trial to compare the immunogenicity of Rotarix (RV1) in infants whose breastfeeding was withheld one hour before through one hour after vaccination with that in infants breastfed at the time of vaccination. The trial was conducted in the peri-urban area of Ibrahim Hyderi in Karachi, Pakistan. Both groups received three doses of RV1 at 6, 10 and 14 weeks of age. Seroconversion (anti-rotavirus IgA antibodies ≥ 20 U/mL in subjects seronegative at 6 weeks of age) following three vaccine doses (6, 10 and 14 weeks) was determined at 18 weeks of age (primary objective) and seroconversion following two doses (6 and 10 weeks) was determined at 14 weeks of age (secondary objective).Results: Four hundred eligible infants were randomly assigned in a 1:1 ratio between the withholding breastfeeding and immediate breastfeeding arms. Overall, 353 (88.3%) infants completed the study according to protocol; 181 in the withholding breastfeeding group and 172 in the immediate breastfeeding group. After three RV1 doses, anti-rotavirus IgA antibody seroconversion was 28.2% (95% CI: 22.1; 35.1) in the withholding arm and 37.8% (95% CI: 30.9; 45.2) in the immediate breastfeeding arm (difference: -9.6% [95% CI: -19.2; 0.2] p = 0.07). After two doses of RV1, seroconversion was 16.6% (95% CI: 11.9; 22.7) in the withholding arm and 29.1% (95% CI: 22.8, 36.3) in the immediate breastfeeding arm (difference: -12.5% [95% CI: -21.2,-3.8] p = 0.005).Conclusions: Withholding breastfeeding around the time of RV1 vaccine administration did not lead to increased anti-rotavirus IgA seroconversion compared with that seen with a breastfeed at the time of vaccination. On the contrary, IgA seroconversion in infants immediately breastfed tended to be higher than in those withheld from a feeding. Our findings suggest that breastfeeding should be continued adlib around the time of rotavirus vaccination and withholding breastfeeding at that time is unlikely to improve the vaccine immunogenicity

Safety and immunogenicity of a parenteral P2-VP8-P[8] subunit rotavirus vaccine in toddlers and infants in South Africa : a randomised, double-blind, placebo-controlled trial

BACKGROUND Efficacy of live oral rotavirus vaccines is reduced in low-income compared with high-income settings. Parenteral non-replicating rotavirus vaccines might offer benefits over oral vaccines. We assessed the safety and immunogenicity of the P2-VP8-P[8] subunit rotavirus vaccine at different doses in South African toddlers and infants. Methods This double-blind, randomised, placebo-controlled, dose-escalation trial was done at a single research unit based at a hospital in South Africa in healthy HIV-uninfected toddlers (aged 2 to <3 years) and term infants (aged 6 to <8 weeks, without previous rotavirus vaccination). Block randomisation (computer-generated, electronic allocation) was used to assign eligible toddlers (in a 6:1 ratio) and infants (in a 3:1 ratio) in each dose cohort (10 μg, followed by 30 μg, then 60 μg if doses tolerated) to parenteral P2-VP8-P[8] subunit rotavirus or placebo injection. The two highest tolerated doses were then assessed in an expanded cohort (in a 1:1:1 ratio). Parents of participants and clinical, data, and laboratory staff were masked to treatment assignment. P2-VP8-P[8] vaccine versus placebo was assessed first in toddlers (single injection) and then in infants (three injections 4 weeks apart). The primary safety endpoints were local and systemic reactions within 7 days after each injection, adverse events within 28 days after each injection, and all serious adverse events, assessed in toddlers and infants who received at least one dose. In infants receiving all study injections, primary immunogenicity endpoints were anti-P2-VP8-P[8] IgA and IgG and neutralising antibody seroresponses and geometric mean titres 4 weeks after the third injection. This trial is registered at ClinicalTrials.gov, number NCT02109484. FINDINGS Between March 17, 2014, and Sept 29, 2014, 42 toddlers (36 to vaccine and six to placebo) and 48 infants (36 to vaccine and 12 to placebo) were enrolled in the dose-escalation phase, in which the 30 μg and 60 μg doses where found to be the highest tolerated doses. A further 114 infants were enrolled in the expanded cohort between Nov 3, 2014, and March 20, 2015, and all 162 infants (12 assigned to 10 μg, 50 to 30 μg, 50 to 60 μg, and 50 to placebo) were included in the safety analysis. Serum IgA seroresponses were observed in 38 (81%, 95% CI 67–91) of 47 infants in the 30 μg group and 32 (68%, 53–81) of 47 in the 60 μg group, compared with nine (20%, 10–35) of 45 in the placebo group; adjusted IgG seroresponses were seen in 46 (98%, 89–100) of 47 infants in the 30 μg group and 47 (100%; 92–100) of 47 in the 60 μg group, compared with four (9%, 2·5–21) of 45 in the placebo group; and adjusted neutralising antibody seroresponses against the homologous Wa-strain were seen in 40 (85%, 72–94) of 47 infants in both the 30 μg and 60 μg groups, compared with three (7%, 1·4–18) of 45 participants in the placebo group. Solicited reactions following any injection occurred with similar frequency and severity in participants receiving vaccine and those receiving placebo. Unsolicited adverse events were mostly mild and occurred at a similar frequency between groups. Eight serious adverse events (one with placebo, two with 30 μg, and five with 60 μg) occurred in seven infants within 28 days of any study injection, none of which were deemed related to study treatment. INTERPRETATION The parenteral P2-VP8-P[8] vaccine was well tolerated and immunogenic in infants, providing a novel approach to vaccination against rotavirus disease. On the basis of these results, a phase 1/2 trial of a trivalent P2-VP8 (P[4], P[6], and P[8]) subunit vaccine is underway at three sites in South Africa.Bill & Melinda Gates Foundation.MJG reports funding from PATH Vaccine Solutions and personal fees from GlaxoSmithKline. AK and LJ report funding from PATH Vaccine Solutions. NP reports honoraria from GlaxoSmithKline, Merck, and Aspen Pharma. SAM reports grants from PATH, grants from Novartis and GlaxoSmithKline, and grants and personal fees from Pfizer and the Bill & Melinda Gates Foundation. MM reports laboratory service agreements with PATH, Merck, and GlaxoSmithKline. IC reports funding from PATH and is a paid consultant for PATH. MP is an employee of PATH, and reports grants from the Bill & Melinda Gates Foundation. AF, JF, LD, and SC declare no competing interests.http://www.thelancet.com/infectionam2017Medical Virolog

Safety and immunogenicity of a parenteral trivalent P2-VP8 subunit rotavirus vaccine : a multisite, randomised, double-blind, placebo-controlled trial

BACKGROUND : A monovalent, parenteral, subunit rotavirus vaccine was well tolerated and immunogenic in adults in the USA and in toddlers and infants in South Africa, but elicited poor responses against heterotypic rotavirus strains. We aimed to evaluate safety and immunogenicity of a trivalent vaccine formulation (P2-VP8-P[4],[6],[8]). METHODS : A double-blind, randomised, placebo-controlled, dose-escalation, phase 1/2 study was done at three South African research sites. Healthy adults (aged 18–45 years), toddlers (aged 2–3 years), and infants (aged 6–8 weeks, ≥37 weeks’ gestation, and without previous receipt of rotavirus vaccination), all without HIV infection, were eligible for enrolment. In the dose-escalation phase, adults and toddlers were randomly assigned in blocks (block size of five) to receive 30 μg or 90 μg of vaccine, or placebo, and infants were randomly assigned in blocks (block size of four) to receive 15 μg, 30 μg, or 90 μg of vaccine, or placebo. In the expanded phase, infants were randomly assigned in a 1:1:1:1 ratio to receive 15 μg, 30 μg, or 90 μg of vaccine, or placebo, in block sizes of four. Participants, parents of participants, and clinical, data, and laboratory staff were masked to treatment assignment. Adults received an intramuscular injection of vaccine or placebo in the deltoid muscle on the day of randomisation (day 0), day 28, and day 56; toddlers received a single injection of vaccine or placebo in the anterolateral thigh on day 0. Infants in both phases received an injection of vaccine or placebo in the anterolateral thigh on days 0, 28, and 56, at approximately 6, 10, and 14 weeks of age. Primary safety endpoints were local and systemic reactions (grade 2 or worse) within 7 days and adverse events and serious adverse events within 28 days after each injection in all participants who received at least one injection. Primary immunogenicity endpoints were analysed in infants in either phase who received all planned injections, had blood samples analysed at the relevant timepoints, and presented no major protocol violations considered to have an effect on the immunogenicity results of the study, and included serum anti-P2-VP8 IgA, IgG, and neutralising antibody geometric mean titres and responses measured 4 weeks after the final injection in vaccine compared with placebo groups. This trial is registered with ClinicalTrials.gov, NCT02646891. FINDINGS : Between Feb 15, 2016, and Dec 22, 2017, 30 adults (12 each in the 30 μg and 90 μg groups and six in the placebo group), 30 toddlers (12 each in the 30 μg and 90 μg groups and six in the placebo group), and 557 infants (139 in the 15 μg group, 140 in the 30 μg group, 139 in the 90 μg group, and 139 in the placebo group) were randomly assigned, received at least one dose, and were assessed for safety. There were no significant differences in local or systemic adverse events, or unsolicited adverse events, between vaccine and placebo groups. There were no serious adverse events within 28 days of injection in adults, whereas one serious adverse event occurred in a toddler (febrile convulsion in the 30 μg group) and 23 serious adverse events (four in placebo, ten in 15 μg, four in 30 μg, and five in 90 μg groups) occurred among 20 infants, most commonly respiratory tract infections. One death occurred in an infant within 28 days of injection due to pneumococcal meningitis. In 528 infants (130 in placebo, 132 in 15 μg, 132 in 30 μg, and 134 in 90 μg groups), adjusted anti-P2-VP8 IgG seroresponses (≥4-fold increase from baseline) to P[4], P[6], and P[8] antigens were significantly higher in the 15 μg, 30 μg, and 90 μg groups (99–100%) than in the placebo group (10–29%; p<0·0001). Although significantly higher than in placebo recipients (9–10%), anti-P2-VP8 IgA seroresponses (≥4-fold increase from baseline) to each individual antigen were modest (20–34%) across the 15 μg, 30 μg, and 90 μg groups. Adjusted neutralising antibody seroresponses in infants (≥2·7-fold increase from baseline) to DS-1 (P[4]), 1076 (P[6]), and Wa (P[8]) were higher in vaccine recipients than in placebo recipients: p<0·0001 for all comparisons. INTERPRETATION : The trivalent P2-VP8 vaccine was well tolerated, with promising anti-P2-VP8 IgG and neutralising antibody responses across the three vaccine P types. Our findings support advancing the vaccine to efficacy testing.The Bill and Melinda Gates Foundationhttp://www.thelancet.comam2020Medical Virolog

Immunogenicity of a Third Scheduled Dose of Rotarix in Australian Indigenous Infants: A Phase IV, Double-blind, Randomized, Placebo-Controlled Clinical Trial

BackgroundRotarix (GlaxoSmithKline) oral rotavirus vaccine is licensed as 2 doses in the first 6 months of life. In settings with high child mortality rates, clinical protection conferred by 2 doses of Rotarix is reduced. We assessed vaccine immune response when an additional dose of Rotarix was given to Australian Aboriginal children 6 to MethodsORVAC is a 2-stage, double-blind, randomized, placebo-controlled trial. Australian Aboriginal children 6 to ResultsBetween March 2018 and August 2020, a total of 253 infants were enrolled. Of these, 178 infants (70%) had analyzable serological results after follow-up; 89 were randomized to receive Rotarix, and 89 to receive placebo. The proportion with seroresponse was 85% after Rotarix compared with 72% after placebo. There were no occurrences of intussusception or any serious adverse events.ConclusionsAn additional dose of Rotarix administered to Australian Aboriginal infants 6 to Clinical trials registrationNCT02941107

Immunogenicity of chimeric haemagglutinin-based, universal influenza virus vaccine candidates: interim results of a randomised, placebo-controlled, phase 1 clinical trial.

BackgroundInfluenza viruses cause substantial annual morbidity and mortality globally. Current vaccines protect against influenza only when well matched to the circulating strains. However, antigenic drift can cause considerable mismatches between vaccine and circulating strains, substantially reducing vaccine effectiveness. Moreover, current seasonal vaccines are ineffective against pandemic influenza, and production of a vaccine matched to a newly emerging virus strain takes months. Therefore, there is an unmet medical need for a broadly protective influenza virus vaccine. We aimed to test the ability of chimeric H1 haemagglutinin-based universal influenza virus vaccine candidates to induce broadly cross-reactive antibodies targeting the stalk domain of group 1 haemagglutinin-expressing influenza viruses.MethodsWe did a randomised, observer-blinded, phase 1 study in healthy adults in two centres in the USA. Participants were randomly assigned to one of three prime-boost, chimeric haemagglutinin-based vaccine regimens or one of two placebo groups. The vaccine regimens included a chimeric H8/1, intranasal, live-attenuated vaccine on day 1 followed by a non-adjuvanted, chimeric H5/1, intramuscular, inactivated vaccine on day 85; the same regimen but with the inactivated vaccine being adjuvanted with AS03; and an AS03-adjuvanted, chimeric H8/1, intramuscular, inactivated vaccine followed by an AS03-adjuvanted, chimeric H5/1, intramuscular, inactivated vaccine. In this planned interim analysis, the primary endpoints of reactogenicity and safety were assessed by blinded study group. We also assessed anti-H1 haemagglutinin stalk, anti-H2, anti-H9, and anti-H18 IgG antibody titres and plasmablast and memory B-cell responses in peripheral blood. This trial is registered with ClinicalTrials.gov, number NCT03300050.FindingsBetween Oct 10, 2017, and Nov 27, 2017, 65 participants were enrolled and randomly assigned. The adjuvanted inactivated vaccine, but not the live-attenuated vaccine, induced a substantial serum IgG antibody response after the prime immunisation, with a seven times increase in anti-H1 stalk antibody titres on day 29. After boost immunisation, all vaccine regimens induced detectable anti-H1 stalk antibody (2·2-5·6 times induction over baseline), cross-reactive serum IgG antibody, and peripheral blood plasmablast responses. An unsolicited adverse event was reported for 29 (48%) of 61 participants. Solicited local adverse events were reported in 12 (48%) of 25 participants following prime vaccination with intramuscular study product or placebo, in 12 (33%) of 36 after prime immunisation with intranasal study product or placebo, and in 18 (32%) of 56 following booster doses of study product or placebo. Solicited systemic adverse events were reported in 14 (56%) of 25 after prime immunisation with intramuscular study product or placebo, in 22 (61%) of 36 after immunisation with intranasal study product or placebo, and in 21 (38%) of 56 after booster doses of study product or placebo. Disaggregated safety data were not available at the time of this interim analysis.InterpretationThe tested chimeric haemagglutinin-based, universal influenza virus vaccine regimens elicited cross-reactive serum IgG antibodies that targeted the conserved haemagglutinin stalk domain. This is the first proof-of-principle study to show that high anti-stalk titres can be induced by a rationally designed vaccine in humans and opens up avenues for further development of universal influenza virus vaccines. On the basis of the blinded study group, the vaccine regimens were tolerable and no safety concerns were observed.FundingBill &amp; Melinda Gates Foundation

B memory cell responses to LPS, IVP and IpaB antigen after oral vaccination with Shigella sonnei vaccine candidates WRSs2 and WRSs3.

B memory (BM) cell responses were evaluated using peripheral blood mononuclear cells that were collected and cryopreserved during a Phase 1 trial of two live Shigella sonnei vaccine candidates WRSs2 and WRSs3. An ELISpot assay was used to measure IgG+ and IgA+ BM cell responses against S. sonnei LPS, IVP and IpaB antigens. Analysis of BM cell responses at baseline, and on days 28 and 56 post vaccination indicate that after a single oral dose of WRSs2 and WRSs3, both groups of vaccinees induced IgG+ and IgA+ BM cell responses that were variable in magnitude among subjects and reached significance to IVP and IpaB at several doses. The responses generally peaked at d28 after vaccination. The baseline as well as post-vaccination levels of IgA+ BM cells were relatively higher than IgG+ BM cells, but the maximum fold-increase at d28/d56 over baseline was greater for IgG+ than IgA+ BM cell responses. Furthermore, at the three highest vaccine doses, >60-90% of subjects were considered responders indicating a ≥2-fold higher IgG+ BM cell responses to IVP and IpaB post vaccination, while fewer subjects indicated the same level of response to LPS