Immunogenicity and safety of a two-dose regimen with hepatitis E virus vaccine in healthy adults in rural Bangladesh: A randomized, double-blind, controlled, phase 2/pilot trial

BACKGROUND

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide and it contributes to considerable maternal and neonatal mortality and morbidity in many low-income countries like Bangladesh. A three-dose regimen of a vaccine against HEV (HEV 239) has shown promising results in China. The effects and safety of this vaccine in other populations and with different dosing regimens remains uncertain.

OBJECTIVES

Investigate the immune response and safety of a two-dose regimen with the HEV 239 vaccine among healthy adults. Examine the feasibility of conducting a larger HEV 239 vaccine trial in rural Bangladesh.

METHODS

One-hundred healthy men and non-pregnant women 16-39 years old were randomized in a 1:1 ratio to receive two doses of either the study (HEV) or control (Hepatitis B virus, HBV) vaccine (at 0, 1 month). Blood samples were collected at day 0, day 60 and 2 years after vaccination. The primary endpoints were the proportion and severity of adverse events up to 2 months after dose one and the longitudinal shift in anti-HEV IgG levels from day 0 to day 60 and 2 years after vaccination.

RESULTS

Adverse events to HEV 239 were comparable to the control vaccine, mild in severity and resolved within one to nine days. All participants in the study group seroconverted and achieved high levels of HEV IgG antibodies that remained positive for two years in all but one. A T-cell response was detected one month after HEV 239 vaccination.

CONCLUSION

Our results show that two doses of the HEV 239 vaccine produces broad and likely functional immune responses against HEV that remain for at least two years. The safety profile was acceptable and a phase four study of HEV 239 in rural Bangladesh is feasible.

CLINICALTRIALS

gov Identifier: NCT02759991.

Stability and Feasibility of Dried Blood Spots for Hepatitis E Virus Serology in a Rural Setting

Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide. In many low-income countries it causes large outbreaks and disproportionally affects pregnant women and their offspring. Surveillance studies to find effective preventive interventions are needed but are hampered by the lack of funding and infrastructure. Dried blood spots (DBS) offer an easier and more robust way to collect, transport, and store blood samples compared to plasma/serum samples, and could ease some of the barriers for such studies. In this study we optimize an HEV IgG ELISA for DBS samples and validate it on 300 paired DBS and plasma samples collected in rural areas of Bangladesh from participants in a HEV vaccine study. We demonstrate that HEV IgG in blood stored as DBS is stable for two months at up to 40 °C, and for five freeze-thaw cycles. The specificity was 97% and the overall sensitivity of the DBS assay was 81%. The sensitivity was higher in samples from vaccinated participants (100%) compared to previously infected participants (59%), reflecting a positive correlation between IgG titer and sensitivity. We found a strong correlation between DBS and plasma samples with an r2 of 0.90, but with a higher degree of difference between individual paired samples. Our study shows that DBS offers a stable alternative to plasma/serum for HEV IgG measurements and can facilitate serological studies, particularly in resource limited areas.

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.

Selection and Interpretation of Scientific Evidence in Preparation for Policy Decisions: A Case Study Regarding Introduction of Rotavirus Vaccine Into National Immunization Programs in Sweden, Norway, Finland, and Denmark

The World Health Organization recommends inclusion of rotavirus vaccines in national immunization programs (NIPs) worldwide. Nordic countries are usually considered comparable in terms of demographics and health-care services and have comparable rotavirus disease burden. Nevertheless, the countries have reached different decisions regarding rotavirus vaccine: Norway and Finland have already introduced rotavirus vaccines into their NIPs and Sweden is currently changing its recommendation and vaccines will now be introduced on a national scale while Denmark has decided against it. This study focuses on the selection and interpretation of medical and epidemiological evidence used during the decision-making processes in Sweden, Norway, Finland, and Denmark. The so-called "severity criteria" is identified as one of the main reasons for the different policy decisions reached across the Nordic countries.

Public health implications of an outbreak of rabies in arctic foxes and reindeer in the Svalbard archipelago, Norway, September 2011

Between 16 September and 5 October 2011 rabies was diagnosed in two arctic foxes and eight reindeer in the Svalbard archipelago, in Norway. This outbreak occurs at the end of the reindeer hunting season and poses an increased risk to many people that were involved in the hunt. As of 28 September 2011, 280 people had received post-exposure prophylaxis. No human cases of rabies have occurred.

Immunogenicity and safety of a combination of two serogroup B meningococcal outer membrane vesicle vaccines

MenBvac and MeNZB are safe and efficacious vaccines against serogroup B meningococcal disease. MenBvac is prepared from a B:15:P1.7,16 meningococcal strain (strain 44/76), and MeNZB is prepared from a B:4:P1.7-2,4 strain (strain NZ98/254). At 6-week intervals, healthy adults received three doses of MenBvac (25 microg), MeNZB (25 microg), or the MenBvac and MeNZB (doses of 12.5 microg of each vaccine) vaccines combined, followed by a booster 1 year later. Two-thirds of the subjects who received a monovalent vaccine in the primary schedule received the other monovalent vaccine as a booster dose. The immune responses to the combined vaccine were of the same magnitude as the homologous responses to each individual vaccine observed. At 6 weeks after the third dose, 77% and 87% of the subjects in the combined vaccine group achieved serum bactericidal titers of > or = 4 against strains 44/76 and NZ98/254, respectively, and 97% and 93% of the subjects achieved a fourfold or greater increase in opsonophagocytic activity against strains 44/76 and NZ98/254, respectively. For both strains, a trend of higher responses after the booster dose was observed in all groups receiving at least one dose of the respective strain-specific vaccine. Local and systemic reactions were common in all vaccine groups. Most reactions were mild or moderate in intensity, and there were no vaccine-related serious adverse events. The safety profile of the combined vaccine was not different from those of the separate monovalent vaccines. In conclusion, use of either of the single vaccines or the combination of MenBvac and MeNZB may have a considerable impact on the serogroup B meningococcal disease situation in many countries.

Outbreak of measles among Irish Travellers in Norway: an update

This is an update on the preliminary report [1] of an outbreak of measles in Norway among a travelling community from England.

An outbreak of measles among a travelling community from England in Norway: a preliminary report

Between 7 and 14 May 2007, Nasjonalt Folkehelseinstitutt (the Norwegian Institute of Public Health, NIPH) was notified of six cases of measles, all occurring in a group of families from England staying at camping sites in Norway.

[Travel vaccination]

Vaccination gives good and long-lasting protection against a number of infectious diseases, and is nearly always recommended before journeys to countries with high risk of contagious diseases. It is important to both renew childhood vaccines and to inoculate against hepatitis A. Vaccines against yellow fever and meningococcal disease are compulsory before entering certain countries. Vaccination against hepatitis B, rabies, typhoid fever and perhaps cholera should be considered for persons spending longer periods in endemic areas. There is a risk of Japanese encephalitis in large parts of South-East Asia, and tick-borne encephalitis in certain areas of Europe.

Safety and immunogenicity of a combined DTPa–IPV vaccine administered as a booster from 4 years of age: A review

A combined DTPa-IPV booster vaccine was administered as a 4th or 5th dose after DTPa or DTPw priming. Over 99% vaccines developed antibody levels considered to be protective to diphtheria, tetanus and poliovirus, and >95% mounted a response to acellular pertussis antigens. Rectal temperature >39.5 degrees C was observed in at most 3.2% of vaccinees. Swelling >50 mm occurred in 24% of DTPa-primed compared to 5.5% of DTPw-primed children. Large swelling involving the entire upper arm (extending to involve the elbow joint) was reported for up to 1.2% of DTPa-primed subjects, which is consistent with literature reports for other DTPa vaccines.

[Young children, pregnant women and travelling abroad]

Pregnant women and parents of young children travelling to non-western countries should consider the risks to which they expose themselves and their children. Travelling during these periods of life needs to be particularly well planned. Travel insurance should cover the whole family, and for pregnant women also the risk of premature birth. Travelling long distances during pregnancy involves a certain amount of risk in itself. This risk could be increased if complications were to occur in areas with a lower standard of health service. As a rule, infants and young children easily adapt to new environments but children abroad should be expected to need a doctor at least as often as at home. Some vaccines and antimalarials must not be used for children below a certain age. Only a few vaccines and antimalarials have been systematically studied in pregnant women in order to exclude teratogenicity. We present some aspects of vaccination and malaria prevention, transport, climate and environment, nutrition, food and drinking water hygiene.

[Should school children receive pertussis vaccine?]

BACKGROUND

A study comparing diphtheria immunity in Norwegian and Russian schoolchildren indicated low immunity against diphtheria in Norwegian children before the booster dose given at age 11 years. The pertussis epidemic in Norway 1997-98 demonstrated decreasing vaccine immunity from age 5-6 years. The possibility of improving immunity against both diseases by a booster dose during early school age is therefore under consideration.

MATERIAL AND METHODS

Immune response and adverse events were studied after a combined vaccine against diphtheria, tetanus, pertussis (acellular) and poliomyelitis (DTPa-IPV) given at seven years of age, and a combined vaccine against diphtheria, tetanus and pertussis (acellular) (DTPa) at 11 years of age, in two parallel trials including 124 and 83 participants respectively.

RESULTS

The trials confirmed that the diphtheria immunity is lower than it ideally should be in more than 40% of children before the booster dose at age 11. Pertussis immunity is difficult to assess because there is no clear relationship between antibody levels and protection. All study participants responded well to all vaccine components. The 11-year-old children reported higher occurrence of adverse events than the 7-year-olds. All adverse events were brief and none were serious.

INTERPRETATION

The results indicate that a booster dose of DTPa-IPV in early school age would give better protection against diphtheria and pertussis in Norwegian schoolchildren, without unacceptable side effects.

[Vaccine against Haemophilus influenzae type b--antibody response and adverse effects]

In 1992 it was decided to implement vaccination against Haemophilus influenzae type b (Hib) in the Norwegian vaccination programme. The chosen vaccine consists of Hib-polysaccharide conjugated to tetanus toxoid. To suit the Norwegian vaccination schedule, Hib-vaccine was given together with vaccine against diphtheria, tetanus and pertussis (DTP) at three, five and ten months of age. Since all earlier studies with the Hib-vaccine have used other time schedules, a pilot study was conducted to test antibody response and side effects when using the Norwegian schedule. 44 infants were vaccinated with Hib-vaccine and DTP at three, five and ten months of age. Blood samples showed that 95% had protective antibody titer against Hib after two doses, 100% after three. The response to the other antigens was adequate. There were only minor side effects. After introduction of the Hib-vaccine the incidence of invasive Hib-infection in children below three years of age has decreased considerably.

[Dystrophy caused by upper airway obstruction]

We describe three infants whose main symptoms were poor weight gain, delayed motor development and recurrent respiratory infections. Obstructive sleep apnea was diagnosed, and all three improved after adenotomy or adenotonsillectomy. Obstructive sleep apnea is an important differential diagnosis in infants showing retarded development and failure to thrive.