Timing of two versus three doses of quadrivalent HPV vaccine and associated effectiveness against condyloma in Sweden: a nationwide cohort study.

OBJECTIVE: To assess incidence of condyloma after two doses of quadrivalent human papillomavirus (qHPV) vaccine, by time since first vaccine dose, in girls and women initiating vaccination before age 20 years. DESIGN: Register-based nationwide open cohort study. SETTING: Sweden. PARTICIPANTS: Girls and women initiating qHPV vaccination before age 20 years between 2006 and 2012. The study cohort included 264 498 girls, of whom 72 042 had received two doses of qHPV vaccine and 185 456 had received all three doses. MAIN OUTCOME MEASURE: Incidence rate ratios (IRRs) of condyloma estimated by time between first and second doses of qHPV in months (m) and age at vaccination, adjusted for attained age. RESULTS: For girls first vaccinated with two doses before the age of 17 years, the IRR of condyloma for 0-3 months between the first and second doses was 1.96 (95% CI 1.43 to 2.68) as compared with the standard three-dose schedule. The IRRs were 1.27 (95% CI 0.63 to 2.58) and 4.36 (95% CI 2.05 to 9.28) after receipt of two doses with 4-7 months and 8+ months between doses, respectively. For women first vaccinated after the age of 17 years, vaccination with two doses of qHPV vaccine and 0-3 months between doses was associated with an IRR of 2.12 (95% CI 1.62 to 2.77). For an interval of 4-7 months between doses, the IRR did not statistically significantly differ to the standard three-dose schedule (IRR=0.81, 95% CI 0.36 to 1.84). For women with 8+ months between dose 1 and dose 2 the IRR was 3.16 (95% CI 1.40 to 7.14). CONCLUSION: A two-dose schedule for qHPV vaccine with 4-7 months between the first and second doses may be as effective against condyloma in girls and women initiating vaccination under 20 years as a three-dose schedule. Results from this nationwide study support immunogenicity data from clinical trials.

Long-term follow-up of successful hepatitis C virus therapy: waning immune responses and disappearance of liver disease are consistent with cure.

BACKGROUND: A sustained viral response (SVR) after interferon-based therapy of chronic hepatitis C virus (HCV) infection is regarded to represent a cure. Previous studies have used different markers to clarify whether an SVR truly represents a cure, but no study has combined a clinical work-up with highly sensitive HCV RNA detection, and the determination of immune responses. AIM: To determine clinical, histological, virological and immunological markers 5-20 years after SVR. METHODS: In 54 patients, liver biochemistry, histology and elastography were evaluated. Liver biopsies, plasma and peripheral blood mononuclear cells (PBMCs) were tested for minute amounts of HCV RNA. HCV-specific T-cell responses were monitored by ELISpot and pentamer staining, and humoral responses by measuring HCV nonstructural (NS)3-specific antibodies and virus neutralisation. RESULTS: Liver disease regressed significantly in all patients, and 51 were HCV RNA-negative in all tissues tested. There was an inverse association between liver disease, HCV-specific T-cell responses and HCV antibody levels with time from SVR, supporting that the virus had been cleared. The three patients, who all lacked signs of liver disease, had HCV RNA in PBMCs 5-9 years after SVR. All three had HCV-specific T cells and NS3 antibodies, but no cross-neutralising antibodies. CONCLUSIONS: Our combined data confirm that a SVR corresponds to a long-term clinical cure. The waning immune responses support the disappearance of the antigenic stimulus. Transient HCV RNA traces may be detected in some patients up to 9 years after SVR, but no marker associates this with an increased risk for liver disease.

Prevailing effectiveness of the 2009 influenza A(H1N1)pdm09 vaccine during the 2010/11 season in Sweden.

Sixty per cent of the Swedish population received the monovalent AS03-adjuvanted pandemic influenza vaccine in the autumn of 2009. We assessed the age-specific effectiveness of this pandemic vaccine against hospitalisation with laboratory-confirmed influenza A(H1N1)pdm09 during the season 2010/11, in the age group from six months to 64 years in Sweden. The screening method was applied to available surveillance data. Our results suggest a prevailing effectiveness of 72% (95% confidence interval (CI): 63­80%) with the highest effectiveness among children, six months to nine years-old (92%, 95%CI: 80­97%). However, there were limitations in data quality and study design due to the lack of systematic recording of administered vaccinations, which underline the importance of preparing for an evaluation when planning for large public health actions. Despite these limitations, we believe the results reflect true, high prevailing vaccine effectiveness. Indeed, there were fewer deaths caused by influenza and the impact of influenza on intensive care units was less severe during the 2010/11 season in Sweden than in countries with lower pandemic vaccination coverage. The association between the pandemic vaccine and narcolepsy has increased the importance of assessing the risks and benefits of the vaccination; studies on the effectiveness and the duration of protection are needed for this.

HCV RNA levels during therapy with amantadine in addition to interferon and ribavirin in chronic hepatitis C patients with previous nonresponse or response/relapse to interferon and ribavirin.

Interferon (IFN) alpha in combination with ribavirin (RIB) is standard therapy for patients with chronic hepatitis C virus (HCV) infection. However, many patients do not respond with sustained HCV clearance to this therapy. At present, no accepted treatment strategy exists for these patients. Recent preliminary data have suggested that amantadine (AMA) is effective against HCV infection. In a pilot study, we treated 13 nonresponders and 10 response/ relapsers to previous IFN/RIB therapy with AMA 200 mg per day in combination with IFN 3 MU thrice weekly, and RIB 1000 mg per day for 24 weeks, with a 24-week follow-up period after end-of-treatment. At the end-of-treatment, 1 previous nonresponder and 5 previous response/relapsers were HCV RNA negative. At the end of follow-up, only 1 previous response/relapser remained HCV RNA negative and had a sustained response. During therapy, serum HCV RNA became undetectable in 4 previous nonresponders, of whom 3 had a breakthrough at week 24. Twenty-one patients continued therapy without dose reductions. One patient discontinued therapy prematurely due to sleeping disturbances, and another patient was withdrawn from therapy due to heavy alcohol intake. We conclude that the addition of AMA to IFN and RIB was well tolerated but had little, if any, impact on HCV RNA eradication in nonresponders or response/relapsers to previous IFN/RIB combination therapy.

Incidence and genetic diversity of group C rotavirus among adults.

Fecal samples from a 1-year prospective study were investigated to establish the role of group C rotavirus infections in acute diarrhea in Swedish adults (>15 years old). Rotaviruses were found in samples from 3% of the patients, and, in 35% of these, group C rotavirus was detected. Clinical symptoms of group C rotavirus infection were generally milder than those of group A rotavirus infection. Gene 8 (vp7) from 12 group C isolates, including strains from the prospective study, a military outbreak, and a sporadic case, was sequenced. The gene was found to be extremely conserved, with identities of 99.1%-100% at the amino acid level. This study has systematically investigated the prevalence and genetic diversity of group C rotavirus in adults. The data confirm the extreme sequence conservation within human group C rotavirus strains and suggest that symptomatic group C rotavirus infections occur more frequently in adults than has been previously recognized.

Role of the enteric nervous system in the fluid and electrolyte secretion of rotavirus diarrhea.

The mechanism underlying the intestinal fluid loss in rotavirus diarrhea, which often afflicts children in developing countries, is not known. One hypothesis is that the rotavirus evokes intestinal fluid and electrolyte secretion by activation of the nervous system in the intestinal wall, the enteric nervous system (ENS). Four different drugs that inhibit ENS functions were used to obtain experimental evidence for this hypothesis in mice in vitro and in vivo. The involvement of the ENS in rotavirus diarrhea indicates potential sites of action for drugs in the treatment of the disease.

Interference of antibody production to hepatitis B surface antigen in a combination hepatitis A/hepatitis B vaccine.

A randomized trial comparing 3 manufacturing consistency lots of a combination hepatitis A/hepatitis B vaccine to each other and to hepatitis A vaccine and hepatitis B vaccine given separately and concurrently was done to evaluate safety, tolerability, and immunogenicity. Healthy volunteers >/=11 years of age were divided into 4 groups. Each of 3 groups received a separate consistency lot of the combination vaccine, and 1 group received separate but concurrent injections of hepatitis A and hepatitis B vaccines. Injections were given at weeks 0 and 24. The combination vaccine was generally well tolerated. The hepatitis A portion of the combination vaccine produced clinically acceptable high seropositivity rates 4 and 52 weeks after the first injection. The hepatitis B portion of the vaccine did not produce clinically acceptable seropositivity rates 4 weeks after the second injection. Lack of antibody production may be attributed, at least in part, to immunologic interference.

Influence of pre-treatment factors on outcome of interferon-alpha treatment of patients with chronic hepatitis C.

A total of 172 Swedish patients treated with interferon-alpha for at least 24 weeks and followed-up > or =24 weeks after treatment was stopped were analysed for pre-treatment factors of importance for achieving a virological sustained response (SR). Furthermore, the predictive value for a virological SR of a positive or negative HCV RNA test at week 12 of treatment was evaluated. A low baseline viral load and genotype non-1b were pre-treatment factors indicating a favourable response. Thus, 44% (38/86) of patients with a low baseline viral load vs. only 16% (14/86) of those with a high viral load had a virological SR (p<0.0001). Of patients with a negative qualitative HCV RNA test after 12 weeks of interferon treatment, 46% (44/95) had virological SR, whereas only 5.9% (4/68) of those with a positive test had (p<0.0001). Prolonged ( > 6 months) treatment with interferon-alpha tended to increase the chance of virological SR (p<0.052).

[The first rotavirus vaccine approved in the USA and Europe]. / Första rotavirusvaccinet godkänt i USA och Europa.

A new live oral rotavirus vaccine (Rotashield) has now been approved both in the USA and Europe. In large multicentre trials involving over 10,000 children, the vaccine has been shown to have a manifest protective effect, first and foremost against severe rotavirus-induced diarrhoea, but to be associated with certain side effects. The Advisory Committee on Immunisation Practices and the American Academy of Paediatrics are now recommending that Rotashield be included in the child vaccination programme. Use of the vaccine in Europe is likely to vary from one country to another. The issue of general recommendations for its use in Sweden should await the results of cost-benefit analysis and review of experience of the vaccine's use in the USA. In addition, a more comprehensive identification of rotavirus serotypes occurring in Sweden is a prerequisite for adequate assessment of the vaccine's necessity in this country.

Encapsulation of rotavirus into poly(lactide-co-glycolide) microspheres.

Two small-scale double emulsion techniques for incorporation of formaldehyde-inactivated rotavirus particles (FRRV) into poly(lactide-co-glycolide) (PLG) microspheres were developed and optimised. The effects of high-speed homogenisation versus vortex mixing on the double emulsion stability, microsphere size, entrapment efficiency and in vitro release of FRRV in the second emulsification step were studied. A stable double emulsion was verified only when using vortex mixing in this step. Slow removal of the organic phase allowed measurement of the size of the emulsion droplets and subsequent prediction of the size of the resulting microspheres. Microspheres in the size range of 1-10 microm were prepared using both techniques. The homogenisation technique was sensitive to changes in the operating time, the emulsification energy and the volume of the outer aqueous phase, while the vortex technique was more robust. Rotavirus was released in vitro in a triphasic manner with both techniques. The more robust vortex technique was selected for preparation of PLG microspheres containing rotavirus for in vivo studies. After immunisation of mice with a single intramuscular injection, the PLG-FRRV microspheres elicited an IgG antibody response in serum detected by ELISA equally high as that elicited with FRRV alone. These results indicate that the antigenicity of FFRV was retained after incorporation into PLG microspheres using the vortex technique.

Incidence and estimates of the disease burden of rotavirus in Sweden.

Laboratory and hospitalization data from two children's hospitals with large primary catchment areas and national laboratory and hospitalization data for children under 4 y of age with acute diarrhoea were compiled to estimate the number of hospitalizations and the cost burden associated with rotavirus diarrhoea in Sweden. According to our estimates 1500-1700 rotavirus-associated hospitalizations occur annually in Sweden in children under 4 y of age (3.7 hospitalizations/1000 children/y). This number represents 2.3% of admissions for all diagnoses in children of this age group. The cost of these hospitalizations is 13.5-15 million Swedish crowns (US$1.8-2 million). Serotyping by PCR for two years revealed that serotype 1 (G1) was the most common (49% and 58%, respectively) identified. Serotypes 2-4 were identified in the following proportions G2 (23% and 5%), G3 (21% and 0%) and G4 (7% and 16%). The national laboratory report data for 1993-96 show that as much as 7-13% of rotavirus infections occur in elderly people.

Confirmation of nosocomial transmission of hepatitis C virus by phylogenetic analysis of the NS5-B region.

Four hepatitis C virus transmission chains at three dialysis units were disclosed by limited sequencing; three of these were disclosed by analysis of the NS5-B region of the genome. Dialysis on the same shift as that during which infected patients were dialyzed was the common factor for seven patients in two chains. Two nurses exposed to needle sticks and their sources of infection constituted two other chains. The strains of three chains belonged to subtype 1a and formed clusters with an intrachain variability of 0 to 6 nucleotides compared to 8 to 37 nucleotides for unrelated strains within this subtype. The clusters were supported by bootstrap values ranging from 89 to 100%.

Virological, biochemical and histological effects of human lymphoblastoid interferon in Swedish patients with chronic hepatitis C.

Thirty-eight Swedish patients with chronic hepatitis C were randomly assigned to receive either 3 million units (MU) or 5 MU of human lymphoblastoid interferon-alpha-n1 (Wellferon) three times per week for either 6 or 12 months. The patients were monitored biochemically, histologically and by quantitative polymerase chain reaction for circulating HCV RNA, during therapy and for the following year. Overall, 22 (58%) of the patients lost detectable hepatitis C virus (HCV) viraemia during therapy but eight of these patients relapsed during follow-up, leaving 14 (37%) sustained responders. Patients infected with HCV non-type 1 genotypes were significantly more likely to achieve a sustained response than were those infected with HCV type 1 (63% vs 10.5%, P = 0.001). Sustained virological responses were also associated with lower pretreatment viraemia level, younger age, absence of cirrhosis and the higher interferon dosage regimens but these associations failed to reach statistical significance. In 97% of patients there was concordance between virological and biochemical responses, and a statistically significant (P = 0.005) improvement in the Knodell histological activity index was observed in the virological sustained responders.

Characterization of a spotted fever group Rickettsia from Ixodes ricinus ticks in Sweden.

A spotted fever group rickettsia isolated from the common tick, Ixodes ricinus, was genetically characterized by PCR and genomic sequencing. This study was performed with nymphal and adult ticks collected in southern and central Sweden. I. ricinus is the only North European tick species of medical importance which is regularly collected from humans. No species of the genus Rickettsia has previously been found in Scandinavian ticks, nor has any case of domestic rickettsial infection in humans or animals been reported. According to the nucleotide sequencing, the present Rickettsia sp. belongs to the spotted fever group of rickettsiae. Ticks are the most common arthropod reservoirs and vectors of the rickettsiae of this group. Among 748 ticks investigated, 13 (1.7%) were positive for a Rickettsia sp. Borrelia burgdorferi was detected in 52 (7%) of the ticks, a prevalence similar to or somewhat lower than that previously been recorded in other Swedish studies. There was no evidence of ehrlichial or chlamydial DNA in these ticks. The Rickettsia sp. was further characterized by 16S ribosomal DNA (rDNA) sequencing and restriction fragment length polymorphism (RFLP). The 16S rDNA sequencing resulted in a sequence identical to that described for Rickettsia helvetica, but the pattern obtained with RFLP of the citrate synthetase gene diverged from previously known patterns. The rickettsial agent of one tick which was positive by PCR was confirmed by transmission electron microscopy. The morphology of this rickettsia was similar to that of the spotted fever and typhus group rickettsiae. This represents the first documented isolate of a Rickettsia sp. from Swedish ticks.

Detection of group C rotavirus in infants with extrahepatic biliary atresia.

The purpose of this retrospective study was to examine liver tissue from patients with cholestatic disease for the presence of group C rotavirus RNA. The reverse transcriptase-polymerase chain reaction (PCR) for genes 5 and 6 was used, and the PCR products were subjected to liquid hybridization with a 32P-labeled probe. A second amplification with nested primers was also used. Samples from 32 subjects (20 with biliary atresia or choledochal cyst and 12 controls) were tested. Ten of 20 biliary atresia patients were positive for group C rotavirus RNA; no controls were positive (P < .003). Three of the positive patients were positive for both genes 5 and 6. Six of the 10 had > 1 sample that was positive. These data suggest a possible relationship between group C rotavirus and extrahepatic biliary atresia in the 10 patients in whom virus RNA was detected.

Serum IgA immune response to individual rotavirus polypeptides in young children with rotavirus infection.

A human IgA-radioimmunoprecipitation assay (IgA-RIPA) utilizing the galactose-binding lectin jacalin from the jack-fruit Artrocarpus integrifolia was developed. Among the human immunoglobulins, jacalin binds specifically to immunoglobulin A. The IgA-RIPA was used to characterize the serum IgA response to individual rotavirus polypeptides in nine paired sera from children (8-34 months of age) with an acute rotavirus infection. In acute sera the IgA response was mainly directed against the inner capsid proteins VP2 and VP6, with VP2 surprisingly being the most immunogenic protein while in the convalescent sera, the IgA response was directed not only against structural but also against non-structural proteins.

Group A rotaviruses produce extrahepatic biliary obstruction in orally inoculated newborn mice.

Extrahepatic biliary atresia is a devastating disease occurring in 1 in 10,000 to 14,000 infants annually in the United States. We have recently described preliminary data suggesting an association of group C rotavirus with biliary atresia in two infants. However, a group C rotavirus animal model of biliary atresia is not presently available. On the other hand, some strains of the better-characterized and much more common group A rotaviruses produce hepatobiliary disease in infant mice. This disease shares many characteristics of the human infection. The present report describes extrahepatic biliary obstruction in immunocompetent BALB/c infant mice infected with a human or animal strain of group A rotavirus. Two-d-old BALB/c mice orally inoculated with hepatobiliary tropic rotavirus were shown to have active virus replication in the biliary tract and liver as early as 48 h postinoculation. At approximately 7 d postinoculation, between one fourth and one half of infant mice, depending on the virus strain, showed signs of inflammation and swelling in the bile ducts. The obstruction was complete in about one half of symptomatic animals. Although there was no obvious atresia as described in human infants, the obstruction was irreversible about 50% of the time, and the resulting fibrosis and bile ductular proliferation in the liver were strikingly similar to those seen in the liver of the human infant with biliary atresia.