Impact of rotavirus vaccine on all-cause diarrhea and rotavirus hospitalizations in Madagascar.

BACKGROUND: Rotavirus vaccine was introduced into the Extended Program on Immunization in Madagascar in May 2014. We analyzed trends in prevalence of all cause diarrhea and rotavirus hospitalization in children <5years of age before and after vaccine introduction and assessed trend of circulating rotavirus genotypes at Centre Hospitalier Universitaire Mère Enfant Tsaralalàna (CHU MET). METHODS: From January 2010 to December 2016, we reviewed the admission logbook to observe the rate of hospitalization caused by gastroenteritis among 19619 children <5years of age admitted at the hospital. In June 2013-December 2016, active rotavirus surveillance was also conducted at CHUMET with support from WHO. Rotavirus antigen was detected by EIA from stool specimen of children who are eligible for rotavirus gastroenteritis surveillance at sentinel site laboratory and rotavirus positive specimens were further genotyped at Regional Reference Laboratory by RT-PCR. RESULTS: Diarrhea hospitalizations decreased after rotavirus vaccine introduction. The median proportion of annual hospitalizations due to diarrhea was 26% (range: 31-22%) before vaccine introduction; the proportion was 25% the year of vaccine introduction, 17% in 2015 and 16% in 2016. Rotavirus positivity paralleled patterns observed in diarrhea. Before vaccine introduction, 56% of stool specimens tested positive for rotavirus; the percent positive was 13% in 2015, 12% in 2016. Diverse genotypes were detected in the pre-vaccine period; the most common were G3P[8] (n=53; 66%), G2P[4] (n=12; 15%), and G1P[8] (n=11; 14%). 6 distinct genotypes were found in 2015; the most common genotype was G2P[4] (n=10; 67%), the remaining, 5, G12[P8], G3[P8], G1G3[P4], G3G12[P4][P8] and G1G3[NT] had one positive specimen each. CONCLUSIONS: Following rotavirus vaccine introduction all-cause diarrhea and rotavirus-specific hospitalizations declined dramatically. The most common genotypes detected in the pre-vaccine period were G3P[8] and G2P[4] in 2015, the post vaccine period.

Rotavirus strain diversity in Eastern and Southern African countries before and after vaccine introduction.

BACKGROUND: The African Rotavirus Surveillance Network has been detecting and documenting rotavirus genotypes in the African sub-continent since 1998 in anticipation of the rollout of rotavirus vaccination in routine Expanded Programme on Immunisation. This paper reports distribution of the rotavirus strains circulating in 15 Eastern and Southern African (ESA) countries from 2010-2015 as part of active World Health Organization (WHO) rotavirus surveillance, and investigates possibility of emergence of non-vaccine or unusual strains in six selected countries post-vaccine introduction. MATERIAL AND METHODS: Stool samples were collected from children <5 years of age presenting with acute gastroenteritis at sentinel hospitals pre- and post-rotavirus vaccine introduction. Samples were tested for group A rotavirus using an enzyme immunoassay by the national and sentinel laboratories. At the WHO Rotavirus Regional Reference Laboratory in South Africa, molecular characterisation was determined by PAGE (n = 4186), G and P genotyping (n = 6447) and DNA sequencing for both G and P types (n = 400). RESULTS: The six-year surveillance period demonstrated that 23.8% of the strains were G1P[8], followed by G2P[4] (11.8%), G9P[8] (10.4%), G12P[8] (4.9%), G2P[6] (4.2%) and G3P[6] (3.7%) in 15 ESA countries. There was no difference in circulating strains pre- and post-rotavirus vaccine introduction with yearly fluctuation of strains observed over time. Atypical rotavirus G and P combinations (such as G1P[4], G2P[8], G9P[4] and G12P[4]) that might have arisen through inter-genogroup or inter-genotypes reassortment were detected at low frequency (2%). Close genetic relationship of African strains were reflected on the phylogenetic analysis, strains segregated together to form an African cluster in the same lineages/sub-lineage or monophyletic branch. CONCLUSION: There has been considerable concern about strain replacement post-vaccine introduction, it was not clear at this early stage whether observed cyclical changes of rotavirus strains were due to vaccine pressure or this was just part of natural annual fluctuations in the six ESA countries, long-term surveillance is required.

Need for a comprehensive, consistently applied national hepatitis B vaccination policy for healthcare workers in higher educational institutions: a case study from South Africa.

BACKGROUND: Hepatitis B virus (HBV) is transmitted by infected blood and other body fluids, placing healthcare workers (HCWs) and student HCWs at increased risk of HBV infection through occupational exposure. AIM: To establish the existence, content and implementation of hepatitis B (HB) vaccination policies for student HCWs being trained at higher educational institutions (HEIs) in South Africa. METHODS: Self-administered structured questionnaires were sent to 23 nursing colleges and 11 universities in South Africa that train doctors, nurses or dentists. FINDINGS: Twelve (35%) questionnaires were returned. Ten HEIs had a policy consisting mainly of recommendations given to students at registration. Nine HEIs made HB vaccinations available, with four HEIs covering the cost through student fees. Seven HEIs did not require a record of previous vaccination. Six HEIs did not accept non-responders (NRs), three HEIs would only accept an NR after receiving a second three-dose vaccination series and counselling, six HEIs regarded an HBV carrier as infectious, and 10 HEIs would accept HBV carriers as students. The low response rate makes it difficult to generalize the results, but may suggest a lack of an HB vaccination policy for student HCWs at non-responding HEIs. CONCLUSIONS: Policies of responding HEIs regarding HB vaccination, HBV carriage and response to HB vaccination were variable, sometimes inappropriate and not sufficiently comprehensive to protect student HCWs against occupationally acquired HBV. This emphasizes the need for a comprehensive, consistently applied, nationally coordinated vaccination policy to ensure that student HCWs receive proper protection against HBV infection.

Impact of HIV Co-Infection on Hepatitis B Prevention and Control: a View from Sub-Saharan Africa

Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections are both endemic in sub-Saharan Africa; warranting high priority efforts in prevention and control. In developed countries; both viruses are transmitted more or less at the same time; and primarily in teenagers and adults. Because the two viruses share major risk factors; a number of HIV-infected individuals will either have past exposure to; or be chronic carriers of HBV. In contrast; HBV is predominantly transmitted in childhood in sub-Saharan Africa; and the majority of inhabitants are already exposed to; or are chronic carriers of HBV by the time they become exposed to HIV for the first time. Nevertheless; there is frequent detection of HBV in HIV-infected individuals (and vice versa) in the region because both viruses are highly endemic. Although there is a limited number of data on the interaction of HIV and HBV in coinfected persons in the sub-Saharan region; reports from around the world have convincingly demonstrated that HIV co-infection can have a negative impact on the transmission; natural history; prevention and control; and treatment of HBV. The impact of HIV co-infection on HBV prevention and control includes; but is not limited to: increased prevalence of HBV in HIV-infected persons; increased HBV infectivity and transmission; accelerated need for HBV therapy due to rapid progression to active chronic hepatitis B; limitation in the choice of drugs (where possible; drugs causing cross-reactivity are avoided in highly active antiretroviral therapy (HAART) regimens until there is a need to treat both viral infections); particularly in the phase of expanding HAART programmes in the region; the need to perform HBV DNA testing in HBsAg-negative sera due to frequent detection of occult hepatitis B in HIV-co-infected persons; and finally; the need for administering additional hepatitis B vaccine doses and ascertaining levels of protective anti-HBs (antibodies against HBsAg) following hepatitis B vaccination

Increased exposure to hepatitis B virus infection in HIV-positive South African antenatal women.

The prevalence of markers for hepatitis B virus (HBV) exposure and active infection in HIV-positive (n=710) and HIV-negative (n=710) pregnant South African women was investigated. The following statistically significant increases in the HIV-positive group were found: anti-hepatitis B core antigen (anti-HBc) (37.3% versus 28.6%; odds ratio [OR]: 1.49); anti-hepatitis B surface antigen (anti-HBs) (29.5% versus 20.1%; OR: 1.66); exposure based on hepatitis B surface antigen (HBsAg) and anti-HBc (39.2% versus 30.1%; OR: 1.49); and exposure based on anti-HBs, anti-HBc and HBsAg (37.1% versus 24.5%; OR: 1.82). However, there was no increase in active HBV infections, with 2.4% of the HIV positives and 2.2% of the HIV negatives being HBV DNA positive. Although the impact that HIV has had on the prevalence of HBV in this population group is not as pronounced as that found in areas of low endemicity (where up to seven-fold increases have been reported), there is a statistically significant increased exposure to HBV.

Hepatitis B virus and human immunodeficiency virus co-infection in sub-Saharan Africa: a call for further investigation.

A growing body of evidence indicates that human immunodeficiency virus (HIV)-positive individuals are more likely to be infected with hepatitis B virus (HBV) than HIV-negative individuals, possibly as a result of shared risk factors. There is also evidence that HIV-positive individuals who are subsequently infected with HBV are more likely to become HBV chronic carriers, have a high HBV replication rate, and remain hepatitis Be antigen positive for a much longer period. In addition, it is evident that immunosuppression brought about by HIV infection may cause reactivation or reinfection in those previously exposed to HBV. Furthermore, HIV infection exacerbates liver disease in HBV co-infected individuals, and there is an even greater risk of liver disease when HIV and HBV co-infected patients are treated with highly active anti-retroviral therapy (HAART). Complicating matters further, there have been several reports linking HIV infection to 'sero-silent' HBV infections, which presents serious problems for diagnosis, prevention, and control. In sub-Saharan Africa, where both HIV and HBV are endemic, little is known about the burden of co-infection and the interaction between these two viruses. This paper reviews studies that have investigated HIV and HBV co-infection in sub-Saharan Africa, against a backdrop of what is currently known about the interactions between these two viruses.

Lack of susceptibility of Chacma baboons (Papio ursinus orientalis) to hepatitis C virus infection.

The main reason to ascertain whether baboons are susceptible to infection with hepatitis C virus (HCV) is the need to replace chimpanzees, which are endangered, as an animal model for undertaking research into the biology and host-virus interactions of HCV, and for developing a vaccine against this virus. A second reason is that baboons are a possible source of xenografts for human liver transplantation. We inoculated serum containing HCV into four Chacma baboons and monitored them for 52 weeks for evidence of infection. Serum was tested for antibody to HCV, HCV RNA, and aminotransferase concentrations at 2-week intervals for 26 weeks and thereafter at 4-week intervals. Liver tissue was examined at 28 and 52 weeks for histopathological changes and viral RNA, and at 52 weeks for viral particles using electron microscopy. Reverse transcription-polymerase chain reaction assay was used to detect HCV RNA, and the results were confirmed by Southern hybridization. Serum aminotransferase concentrations remained within the normal range and liver histology was normal during the follow-up period. Passive transmission of anti-HCV to the baboons was observed during the first 4 weeks. HCV RNA was not detectable in any serum or liver sample and electron microscopy failed to reveal viral particles in liver tissue. In conclusion, we did not find Chacma baboons to be susceptible to infection with HCV, although we cannot deny that in an immunosuppressed liver transplant recipient, infection of a baboon xenograft might occur. Another animal model for HCV infection must be sought.

The first five years of universal hepatitis B vaccination in South Africa: evidence for elimination of HBsAg carriage in under 5-year-olds.

South Africa implemented a vaccine against hepatitis B virus (HBV) into the Expanded Programme on Immunisation (EPI) in April 1995. The HBV vaccine is given at 6, 10, and 14 weeks, in parallel with OPV, DTP and Hib vaccines. This study assessed the impact of universal childhood HBV vaccination programme in reducing HBsAg carriage, in the first five years (1995--1999) since its implementation. In parallel, we investigated the current burden of HBV infection in mothers of vaccinees and the adult general population. A total of 598 babies (mean age=23.3 months) who received 3 doses of 1.5 microg/0.5 ml Hepaccine-B (Cheil) were recruited from the Northern Province (one of the nine provinces in South Africa). HBsAg, anti-HBs, anti-HBc, HBeAg and anti-HBe were tested using the IMx or Axsym kits (Abbott Laboratories). PCR assays were performed following established protocols. The overall seroprotection rate (i.e. anti-HBs titre> or =10 mIU/ml) was 86.8% (519/598) in vaccinated babies, while 13.2% had anti-HBs levels<10 mIU/ml. Seroprotection rates and geometric mean titres (GMT) decreased significantly with increasing age, possibly reflecting waning anti-HBs titre over time. Total HBV exposure (positive for either HBsAg, anti-HBs, or anti-HBc) was 31.0% (58/187) in mothers of vaccinees and 40% (72/180) in the adult general population. HBsAg carrier rate was virtually similar in both groups (3.2% in mothers of vaccinees vs. 3.3% in the general population). Against this background, no vaccine failures resulting in HBsAg and HBV DNA positivity were seen in vaccinated babies, including 6 babies born to HBsAg positive carrier mothers (one carrier mother was positive for HBeAg and HBV DNA). However, 0.9% (5/582) babies, aged between 8--11 months, tested positive for anti-HBc, all of whom had anti-HBs titres>10 mIU/ml and were negative for HBV DNA. Anti-HBc positivity was probably maternal in origin, or may represent sub-clinical averted HBV infections. It can be concluded that the HBV vaccine is highly effective within the framework of the South African EPI and already shows a positive impact in the elimination of HBsAg carrier rate in children<5 years.

Rotavirus strains bearing the VP4P[14] genotype recovered from South African children with diarrhoea.

Human rotavirus VP4P[14] strains were previously recovered in South Africa [18]. The strains exhibited a long RNA pattern, VP6 subgroup II and VP7 serotype G1. Two of the VP8 genes were cloned and sequenced and demonstrated a high nucleotide homology with the prototype P[14] strains (PA169 and HAL1166).

Age related prevalence of hepatitis G virus in South Africans.

AIM: To investigate the age related prevalence of hepatitis G virus (HGV) infection and its mode of transmission in relation to hepatitis B (HBV) and C (HCV) co-infection in South African blacks. METHODS: Reverse transcriptase polymerase chain reaction was performed to detect active infection, using primers for the 5'-NCR, NS5a, and NS3 regions. Antibodies to HGV envelope-2 protein (anti-E2), which measures past infection, were also sought. RESULTS: The overall prevalence of active infection was 116/580 (20%). A higher prevalence was noted in HBsAg carriers (28/106; 26.4%) and HCV positive subjects (25/82; 30.5%). In contrast to developed countries, active and past infection was seen in 12.9% and 12.1% of the general population, respectively (subjects negative for HBsAg and anti-HCV markers and with normal alanine aminotransferase values), with a total prevalence of 21.1% (52/248). Viraemia and anti-E2 were almost mutually exclusive. The distribution of viraemia by age was: < or = 15 years, 20/223 (9.0%); 16-35 years, 42/147 (28.6%); > or = 36 years, 37/151 (24.5%), with a significant difference (p = 0.001) in age related prevalence. A similar trend was observed for the prevalence of past infection in the general population. CONCLUSIONS: HGV infection begins in childhood and increases with age in South Africa, but transmission is largely independent of HBV and HCV. No association was found between HGV viraemia and hepatitis, or with co-infection with either HBV or HCV.

HGV: the identification, biology and prevalence of an orphan virus.

Hepatitis G virus (HGV) and GB virus C (GBV-C) (both hereinafter referred to as HGV) were independently identified in patients with hepatitis of unknown aetiology. HGV is a positive-sense RNA virus of the family Flaviviridae. The virus can establish both acute and chronic infection and appears to be sensitive to interferon. Horizontal transmission is mainly parenteral, although other routes such as vertical have been well documented. High risk groups include intravenous drug users (i.v.DUs), the multiply transfused, haemodialysis patients and haemophiliacs. Up to 90% of i.v.DUs are positive for either HGV-RNA or antibodies to HGV envelope-2 protein (anti-E2). HGV is frequently detected in patients with HBV and HCV infection. Its link to hepatitis has now become less certain. Only around 3-6% of non-A E hepatitis cases are HGV viraemic, clearly showing that HGV is not the major cause of idiopathic hepatitis as originally hoped. Around 1-5% of volunteer blood donors in developed countries are HGV viraemic, but the prevalence is 10-20% in the general population in some developing countries. At present, it is not known whether HGV is associated with other diseases in humans, is a passenger virus, or only becomes virulent under certain conditions.

Transmission of a homogenous hepatitis B virus population of A1896-containing strains leading to mild resolving acute hepatitis and seroconversion to hepatitis B e antigen antibodies in an adult.

The pre-core variant, A1896, which switches off hepatitis B e antigen (HBeAg) production, is common in hepatitis B e antigen antibody (anti-HBe)-positive chronic hepatitis patients. It has been observed in occasional case reports of acute hepatitis. However, transmission in the absence of HBeAg-producing strains, leading to acute nonfulminant hepatitis and clearance in adults, has not been reported. Here, we show that this event can occur, further confirming that A1896 strains are "wild-type" and can lead to all the same outcomes as G1896 strains. This is in keeping with phylogenetic evidence that A1896 is transmitted independently on a large scale in the population and explains anti-HBe- positive persons who have not had an HBeAg-positive phase documented.

Relative frequency of human rotavirus VP4 (P) genotypes recovered over a ten-year period from South African children with diarrhea.

The relative frequency and distribution of the VP4 (P) genotypes of 227 human rotavirus field strains were investigated in South Africa. The stool samples were collected between 1984-1993 from infants and young children with diarrhea at Ga-Rankuwa Hospital, Pretoria, South Africa. The RNA was extracted from stools, heat denatured, and dot blotted onto nylon membranes. The blots were hybridized to PCR-generated, 32P radio-labelled VP4-specific probes (corresponding to the hyperdivergent region of the VP4 gene) of the following human rotavirus VP4 genotypes: P4, P6, P8, P9, P10, and P12. Of the 157 rotavirus strains typed by the probes, the P8 genotype was identified most frequently in 63.7% (n = 100) of the samples. The P4 and P6 genotypes were detected less frequently in 22.3% (n = 35) and 8.3% (n = 13) of the samples, respectively. Five cases of dual infection between P8 and P4 genotypes occurred, indicating the potential for reassortment between members of different rotavirus genogroups. The P9 genotype could not be confirmed in 3 cases (1.9%), while the P10 genotype was not observed at all, indicating the scarcity or absence of these VP4 genotypes in this region. Interestingly, we identified the newly-described P12 VP4 genotype in 6 cases (3.8%), suggesting a wide geographical distribution. Furthermore, several samples with sufficient RNA by gel electrophoresis remained untyped by the probes used in this study, and may represent putative "new" human VP4 genotype(s).

Geographic distribution of human rotavirus VP4 genotypes and VP7 serotypes in five South African regions.

The rotavirus outer capsid proteins elicit the production of neutralizing antibodies and are known to play a role in inducing resistance to disease. In this study, cDNA probes directed at the six most common human rotavirus VP7 serotypes (G1 to G4, G8, and G9) and five human rotavirus VP4 genotypes (P4, P6, P8, P9, and P10) were utilized. Hybridization analysis of 572 human rotavirus strains collected from five regions in South Africa was performed to determine the distribution of the VP7 serotypes and VP4 genotypes in nature. VP7 serotype G1 was identified most frequently, occurring in 51% of the rotavirus strains tested. VP7 serotypes G2 and G4 occurred in similar numbers, although their distribution varied regionally. Few serotype G3 strains and no G8 or G9 strains were identified. The P8 VP4 genotype occurred most frequently overall (66%), and the P4 genotype was detected next most frequently. The P6 genotype was identified in 28 symptomatically infected neonates and in 8 symptomatic infants. Few P9 strains were identified. The potential for reassortment events was demonstrated by dual infections with different viruses.