Hepatitis B infection control in Colombian Amazon after 15 years of hepatitis B vaccination. Effectiveness of birth dose and current prevalence

BackgroundHepatitis B virus (HBV) infection is highly endemic in the Colombian Amazon basin. In Colombia, the universal hepatitis B vaccination in that area has been active since 1993. The program targets children aged under five years. Newborns receive at least three doses, and in 2001, HBV vaccine birth dose was included. This study aimed to evaluate the advances on HBV control in the Colombian Amazon.MethodsA population-based cross-sectional study was conducted in children less than 11 years old in rural areas of the Colombian Amazon, in order to assess the current levels of HBV prevalence and evaluate the effectiveness of HBV vaccination. Participants were selected from villages scattered along the Amazon, Putumayo and Loretoyaco Rivers. Blood samples were taken from children. All the samples were examined for surface antigen (HBsAg) and IgG antibodies against core antigen (AntiHBc) of HBV. Data on HBV vaccination status and other risk factors were also collected.ResultsBlood samples from 1275 children were included in the study. The positivity for IgG AntiHBC and HBsAg was 3.8% and 0.5%, respectively. It was observed that receiving a dose of HBV vaccine within 48 h after birth decreased the risk of HBV infection and carriage by 95%. Being born to an AntiHBc positive mother increased 8 times the risk of HBV infection (OR  =  7.8 CI 95% 3.3–10.2) and 7 times the risk of HBsAg carriage (OR  =  6.6 CI 95% 2.1–10.1).ConclusionThe prevalence of HBV infection and HBsAg carriage continues to decrease among children living in the Colombian Amazon. The high protective effectiveness of an HBV birth does suggest that perinatal transmission is important in endemic areas of Latin America, an aspect that has not been fully studied in the region.     

Distribution of invasive Streptococcus pneumoniae serotypes before and 5 years after the introduction of 10-valent pneumococcal conjugate vaccine in Brazil

BackgroundIn March 2010, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced into the routine immunization program in Brazil. We describe the pneumococcal serotypes that caused invasive pneumococcal diseases (IPD) before and after the introduction of PCV10 using data from a national laboratory-based surveillance system.MethodWe compared the prevalence of vaccine types (VT) and non-vaccine types (NVT) of Streptococcus pneumoniae in three periods, pre-PCV10 (January/2005-December/2009), early post-PCV10 (January/2010-December/2013), and late post-PCV10 (January/2014-December/2015), by episode in meningitis and non-meningitis cases and by age group. Changes in serotype prevalence in the early and late post-PCV10 periods were determined using pre-PCV10 period as a reference.ResultsA total of 8971 IPD isolates from patients aged 2 months to 99 years were analyzed. In the late post-PCV10 period, the VT-IPD reduction in the 2-month to 4-year age group was 83.4% for meningitis and 87.4% for non-meningitis cases; in the age groups 5–17 years, 18–64 years, and ≥65 years, VT declined by 56.1%, 54.1%, and 47.4%, respectively, in meningitis cases, and by 60.9%, 47.7%, and 53.4%, respectively, in non-meningitis cases. NVT-IPD increased throughout the study period, driven mainly by serotypes 3, 6C, and 19A, which remained the predominant types causing IPD in the late post-PCV10 period.ConclusionWe observed direct and indirect PCV10 protection against IPD caused by VT and a shift in the distribution of serotypes 5 years after the introduction of PCV10. Continued IPD surveillance is needed to evaluate the sustainability of the high prevalence of serotypes 3, 6C, and 19A, which were not included in PCV10.     

Characteristics of immune memory 10–15 years after primary hepatitis B vaccination

Background and aimsThe definition of immune memory after hepatitis B vaccination is still under debate. Therefore, we analysed hepatitis B surface antigen (HBsAg)-specific memory in more detail by investigating the kinetics of humoral and cellular responses after hepatitis B booster vaccination.MethodsThe anti-HBs kinetics of 23 individuals with anti-HBs titres below 10 IU/l, who had been vaccinated 10–15 years ago, was monitored at day 0, 3, 7, 14 and 28 after booster vaccination. HBsAg-specific IFNγ- and IL5-secreting cells in enriched CD4⁺ fraction were measured at day 0, 7 and 28 post-booster by enzyme-linked immunospot assay (ELISpot).Results22 of 23 subjects showed similar anti-HBs kinetic curves, including 3 of 4 subjects who did not reach anti-HBs titres of 10 IU/l. The steep anti-HBs increase started between day 3 and 7 and peaked around day 14. A plateau or only minimal changes were visible between day 14 and 28. 17.4% of subjects showed pre-booster cellular responses, and this rate had increased to 47.8% and 56.5% after 7 and 28 days, respectively. The kinetic patterns of T cell responses differed considerably among subjects. A dominance of Th2 responses (IL5 secretion) over Th1 responses (IFNγ secretion) could be observed.ConclusionsThe presence of B cell memory could be shown by a typical anamnestic anti-HBs response curve after a booster dose in all but one individual. In contrast, T cell responses to booster vaccination, which occurred in approximately 50% of participants, were rather heterogeneous.     

Impact and effectiveness of pentavalent rotavirus vaccine in children <5 years of age in Burkina Faso

BackgroundBurkina Faso was one of the first African nations to introduce pentavalent rotavirus vaccine (RV5, RotaTeq) into its national immunization program in October 2013. We describe the impact and effectiveness of rotavirus vaccine on acute gastroenteritis (AGE) hospitalizations among Burkinabe children.MethodsSentinel hospital-based surveillance for AGE was conducted at four hospitals during December 2013 – February 2017. Demographic, clinical, and vaccination information was collected and stool specimens were tested by EIA. Trends in rotavirus AGE hospitalizations and changes in the proportion of AGE hospitalizations due to rotavirus were examined at two sentinel sites from January 2014 – December 2016. Unconditional logistic regression models using data from all 4 surveillance sites were used to calculate vaccine effectiveness (VE, defined as 1-odds ratio) by comparing the odds of vaccination among rotavirus AGE (cases) and non-rotavirus AGE (controls) patients, controlling for age, season, hospital site and socioeconomic factors.ResultsThe proportion of AGE hospitalizations that tested positive for rotavirus declined significantly among children <5 years of age, from 36% (154/422) in 2014 to 22% (71/323, 40% reduction, p < .01) in 2015 and 20% (61/298, 44% reduction, p < .01) in 2016. Among infants, the percentage of AGE admissions due to rotavirus fell significantly from 38% (94/250) in 2014 to 21% (32/153, 44% reduction, p < .01) in 2015 and 17% (26/149, 54% reduction, p < .01) in 2016. The adjusted VE for full 3-dose series of RV5 against rotavirus hospitalization was 58% (95% [CI], 10%, 81%) in children 6–11 months of age and 19% (−78%, 63%) in children ≥12 months.ConclusionRotavirus hospitalizations declined after introduction of pentavalent rotavirus vaccine in children, particularly among infants. RV5 significantly protected against severe rotavirus gastroenteritis in infants, but effectiveness decreased in older children.     

Safety and immunogenicity of hepatitis E vaccine in elderly people older than 65 years

BackgroundHepatitis E virus (HEV) infection is a leading cause of acute hepatitis worldwide, and results in high morbidity and mortality rates among elderly people in China. The hepatitis E vaccine, Hecolin®, has been shown to be safe and highly efficacious among healthy adults aged 16–65 years old. However, there is no data about Hecolin® vaccination in elderly people older than 65 years (y).MethodsAn open-labeled, controlled trial was conducted to evaluate the safety and immunogenicity of Hecolin® among the elderly aged >65 y. A total of 601 eligible participants were enrolled. Among them, 200 elderly people aged >65 y and 201 adults aged 18–65 y were assigned to the Hecolin® groups and vaccinated at day 0, month 1 and month 6. Serum samples were collected for anti-HEV IgG determination at day 0 prior to immunization and at month 7. The remaining 200 elderly people aged >65 y were assigned to the safety control group and received no intervention but were instructed to report any adverse events that occurred during the whole study period in the same way as those in the Hecolin® groups.ResultsAfter receiving 3 doses of Hecolin® with the standard schedule, most (96.7%) of the vaccinated elderly people aged >65 y seroconverted at one month after the final dose (month 7). At month 7, the geometric mean concentrations of anti-HEV IgG were 5.36 (95% CI, 3.88–7.41) and 19.65 (95% CI, 16.81–22.98) among the baseline seronegative and seropositive elderly, respectively. Of the vaccinated elderly, 97.3% (177/182) had anti-HEV IgG levels higher than 1.0 WU/ml at month 7. Hecolin® was very well tolerated in this population. No vaccine-related SAEs were reported.ConclusionsHecolin® is immunogenic and well tolerated in elderly people aged greater than 65 years.     

Observational study of vaccination in cancer patients: How can vaccine coverage be improved?

BackgroundChemotherapy increases the risk of infections, often severe, and some of them are vaccine-preventable infections. We aimed to assess vaccination coverage and associated factors in oncology and hematology patients.MethodsConsecutive adult patients followed in a French university hospital for hematological malignancy or solid cancer voluntarily completed an anonymous questionnaire in September and October 2016. It included questions on underlying disease, chemotherapy, flu, and pneumococcal vaccination uptakes, and attitudes toward vaccination. Factors associated with vaccination uptake were assessed by multivariate logistic regression.ResultsThe response rate was 41.9% (N = 671) among 1,600 questionnaires distributed; 232 patients had underlying hematological malignancy and 439 had solid cancer. Half of the patients were aged over 65 years. Chemotherapy was ongoing or discontinued for less than one year in 74.7% of patients. In patients aged < 65 years undergoing chemotherapy, flu vaccination rate was 19.9% whereas patients aged > 65 years had coverage of 47%. Pneumococcal vaccine uptake was 7.3%. However, 64.7% of patients were favorable to vaccination. Vaccine uptake was associated with age > 65 years (OR 4.5 [2.9–7.0]), information about vaccination delivered by the family physician (OR 12.9 [5.5–30.1]), follow-up in hematology unit (OR 2.0 [1.3–3.1]), and positive opinion about vaccination (OR 2.0 [1.3–3.1]).ConclusionDespite specific recommendations regarding immunocompromised patients, anti-pneumococcal and flu vaccinations were rarely conducted, even in elderly patients. Targeted information campaigns to family physicians, oncologists, and patients should be implemented to improve vaccine coverage in patients with underlying malignancies.     

The end of the Australia antigen? An ecological study of the impact of universal newborn hepatitis B vaccination two decades on

Background

A universal newborn hepatitis B (HBV) vaccination program was introduced in the Northern Territory of Australia in 1990, followed by a school-based catch-up program. We evaluated the prevalence of hepatitis B infection in birthing women up to 20 years after vaccination and compared this to women born before the programs commenced.

Methods

A cohort of birthing mothers was defined from Northern Territory public hospital birth records between 2005 and 2010 and linked to laboratory confirmed notifications of chronic HBV, based principally on a record of hepatitis B surface antigen detection. Prevalence of HBV was compared between women born before or after implementation of the newborn and catch-up vaccination programs.

Findings

Among 10797 birthing mothers, 138 (1.3%) linked to a chronic HBV record. HBV prevalence was substantially higher in Aboriginal women compared to non-Indigenous women (2.4% versus 0.04%; p < 0.001). Among 5678 Aboriginal women, those eligible for catch-up and newborn HBV vaccination programs had a significantly lower HBV prevalence than older women born prior to the programs: HBV prevalence respectively 2.2% versus 3.5%, (OR 0.61, 95%CI 0.43–0.88) and 0.8% versus 3.5% (OR 0.21, 95%CI 0.11–0.43). This represents a risk reduction of respectively 40% and 80% compared to unvaccinated women.

Interpretation

The progressively greater reduction in the prevalence of chronic HBV in adult Aboriginal women co-inciding with eligibility for catch-up and newborn vaccination programs is consistent with a significant impact from both programs. The use of data derived from antenatal screening to track ongoing vaccine impact is applicable to a range of settings globally.     

Factors associated with effectiveness of the first dose of hepatitis B vaccine in China: 1992–2005

Background

In China, the prevalence of chronic hepatitis B infection was high because of perinatal and early childhood transmission. A three-dose hepatitis B vaccine schedule with a first dose as soon as possible after birth was introduced in 1992 and generalized in 2002 in the Expanded Programme of Immunization (EPI). In 2006, a serological survey evaluated the effectiveness of vaccination.

Methods

We conducted a restricted analysis of the national serological survey that sampled children and collected information on demographic characteristics, birth history, hepatitis B vaccination and hepatitis B surface antigen (HBsAg) status as determined by ELISA testing. We compared children who received the first dose in a timely way (i.e., within 24 h of birth) with others in terms of HBsAg status, stratified by birth cohort and place of birth.

Results

Three-dose hepatitis B vaccine coverage increased from 60.8% for children born in 1992–1997 to 93.2% for children born in 2002–2005. Meanwhile, timely birth dose coverage increased from 38.7% to 74.4%. Among 29,410 children born in 1992–2005 who had received three vaccine doses and no hepatitis B immune globulin, factors associated with being HBsAg-negative in multivariate analysis included receiving a timely birth dose (p = 0.04), birth after 1998 (p < 0.001), living in an urban setting (p = 0.008) and hospital birth (p = 0.001). The relative prevalence of HBsAg among children receiving the timely birth dose was lower for children born in county or larger hospitals (0.39), intermediate in township hospitals (0.73) and highest at home (0.87).

Conclusions

Hospital birth and receiving a timely birth dose are the main determinants of the field effectiveness of the first dose of hepatitis B vaccine. Efforts to increase the proportion of hospital deliveries are key to increasing timely birth dose coverage and its effectiveness.     

The effectiveness of shingles vaccine among Albertans aged 50 years or older: A retrospective cohort study

PurposeWe assessed the effectiveness of shingles vaccine in preventing incident shingles among Alberta residents aged 50 years or older over the period 2009 – 2015, using administrative health data.MethodsThe cohort comprised of Albertans from the Alberta Health Care Insurance Plan Registry (AHCIP) as of June 30, 2009 and aged 50 years or older. Those who received shingles vaccine were identified from the provincial pharmaceutical information network. The occurrence of incident shingles was identified through both inpatient and outpatients/community care data. Incident shingles was defined as the earliest dated record of ICD 9-CM 053 or ICD-10-CA B02. Starting on November 1, 2009, individuals with no history of shingles or shingles vaccination were followed until Nov 1, 2015 (6 years), or until shingles incidence, death, or AHCIP cancellation (including leaving Alberta). Vaccine effectiveness (VE) was estimated as the inverse of the relative risk of developing incident shingles in each year following vaccination compared to time at risk without vaccination, while adjusting for age, sex, income quintile, and immune compromising conditions (identified from physician claims, inpatient, and cancer registry data).ResultsThere were 1,094,236 individuals in the cohort, with 85,439 (7.80%) vaccinated individuals. The shingles incidence rate was 9.03 [95% CI: 8.95, 9.11] cases per 1,000 person years (49,243 cases). Adjusted VE in the first year following immunization was 50.02% [95% CI: 44.71%, 54.83%] against incident shingles, decreasing to no effect by the fifth year (VE = 14.00% [95% CI: −20.99%, 38.88%]).ConclusionsOur findings are consistent with observations from other population based studies and provide population level data for policy-makers to review when making decisions related to public funding of shingles vaccine.     

Significance and anamnestic response in isolated hepatitis B core antibody-positive individuals 18 years after neonatal hepatitis B virus vaccination in Taiwan

Aim

To investigate the significance of isolated hepatitis B core antibody (anti-HBc) and to analyze the response to hepatitis B virus (HBV) booster vaccination in young adults with isolated anti-HBc who had been fully vaccinated with HBV vaccine as infants.

Materials and methods

We screened 1734 new university entrants who had been fully vaccinated against HBV in infancy for the presence of hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and anti-HBc upon university entry. Results positive for isolated anti-HBc were reconfirmed by testing for the presence of HBsAg and anti-HBc once more, and further evaluated for anti-HCV, anti-HIV, and HBV DNA status 6 months later. Students were also offered HBV booster vaccinations at that time. Geometric mean titers (GMT) of anti-HBs after one booster dose of HBV were compared between students with isolated anti-HBc and students with HBV naïve status.

Results

The overall prevalence of isolated anti-HBc in our student cohort was 1.2% (21 of 1734). No evidence of occult HBV infection was observed. A “booster” anamnestic response (anti-HBs titer ≥10 mIU/mL) was noted in 95% (20 of 21) of subjects with isolated anti-HBc. After re-measurement of anti-HBc, 13 (62%) of the 21 subjects with isolated anti-HBc were reclassified as having resolved HBV infection with a loss of anti-HBs. In the remaining 8 subjects (38%), isolated anti-HBc was determined to be false positive. The HBV status of these 8 subjects was HBV naïve due to the waning-off effect of anti-HBs of the neonatal HBV vaccination. There was no significant difference in anamnestic response to a single HBV booster dose of vaccine between students with isolated anti-HBc (n = 13) and those with HBV naïve (n = 323) status (GMT 50.6 vs 47.7 mIU/mL, P = 0.90).

Conclusion

The presence of isolated anti-HBc 18 years after HBV vaccination can be attributed to post-HBV infection with a loss of anti-HBs and to a decline in anti-HBs elicited by vaccine. A single HBV booster dose of vaccine is recommended for subjects with isolated anti-HBc who were fully vaccinated with HBV vaccine as infants. This finding needs to be replicated in further studies with larger cohorts.     

Preparing for rotavirus vaccine introduction – A retrospective assessment of the epidemiology of intussusception in children below 2 years of age in Nepal

BackgroundRotavirus is the most common cause of severe diarrhea in Nepali children, accounting for 25–33% of childhood diarrhea hospitalizations. Two rotavirus vaccines recommended for inclusion in national immunization programs have been associated with a low risk of intussusception in post-marketing studies conducted in several countries. Data on the epidemiology of intussusception hospitalizations are lacking in Nepal. Thus, we aimed to describe the epidemiology of intussusception-associated hospitalizations among Nepali children in preparation for rotavirus vaccine introduction.MethodsA retrospective review of intussusception hospitalizations for a three year period was conducted at two major pediatric hospitals in Kathmandu, Nepal. Possible intussusception cases were identified through admission, discharge, and operation theater logs and ultrasound registers. Cases with a diagnosis of possible intussusception were selected for medical record review and classified as confirmed if they met the Brighton Collaboration level 1 criteria of diagnostic certainty and the child was aged < 24 months. Data on demographics, clinical course, and outcome were abstracted and analyzed.ResultsEight-five confirmed intussusception cases were identified; most (96%) were confirmed at surgery. The number of intussusception cases peaked between ages 4–7 months; no cases occurred in children 0–2 months. Fifty-nine (64%) case-patients were male. The median duration of symptoms before admission was 2 days (range: 0–14). Abdominal pain, bloody stool, and vomiting were the most common clinical features. All cases underwent surgical treatment; there was only one death.ConclusionsThis is the first study to evaluate the epidemiology of intussusception hospitalizations among children aged < 24 months in Nepal. Because the public health impact of rotavirus vaccination could be substantial in Nepal, where childhood diarrhea-related morbidity and mortality are high, this baseline knowledge of intussusception prior to introduction of rotavirus vaccine in the national immunization schedule will provide useful information for post-vaccine introduction safety monitoring.     

Seroprevalence of rubella antibodies in the State of São Paulo,Brazil, 8 years after the introduction of vaccine

Rubella vaccine was introduced in the official immunization calendar of the State of S?o Paulo, in 1992, at 15 months of age, following a mass vaccination targeting all children between 1 and 10 years of age. This mixed strategy was designed taking into account serological data and mathematical models to estimate the optimal ages for vaccination. To evaluate the efficacy of routine vaccination on rubella infection in S?o José do Rio Preto, State of S?o Paulo, 8 years after the introduction of vaccine, a seroprevalence survey was carried out in December 2000, comprising 1,536 subjects aging from 6 months to 25 years. Rubella specific IgG was detected in blood samples by enzyme-linked immunosorbent assay (ELISA). From 18 months to 5 years of age (covered by a mass vaccination campaign 6 months before the study) the seroprevalence was above 90%. From 6 to 8 years of age (vaccinated by routine schedule at 15 months), the seroprevalence was 76%. From 9 to 18 years of age (vaccinated at the mass campaign that introduced the vaccine 8 years before) the seroprevalence was about 85%. After 20 years of age, protection was acquired by previous infection, as they were not covered by any vaccine program. From 20 to 25 years of age, the seroprevalence was 70%. As the seroprevalence remains low at ages not vaccinated, it should be expected low infection rates at this age window. Despite this, the present situation deserves care, as routine vaccination is given a protection below the minimum level necessary (80%). The efficacy of the proposed strategy depends on better routine vaccination coverage. A second dose of vaccine should also be considered.     

Antibody persistence and booster response 68 months after vaccination at 2–10 years of age with one dose of MenACWY-TT conjugate vaccine

BackgroundWe evaluated antibody persistence up to 68 months (M) post-vaccination with a quadrivalent meningococcal serogroups A, C, W and Y tetanus toxoid conjugate vaccine (MenACWY-TT) or a licensed monovalent MenC conjugate vaccine (MenC-CRM₁₉₇) and subsequent booster responses to MenACWY-TT in healthy European children.MethodsIn the initial study (NCT00674583), healthy children, 2–10 years of age, were randomized to receive a single dose of either MenACWY-TT or MenC-CRM₁₉₇. In the follow-up study, we present the persistence at 32, 44, 56, and 68 M post-vaccination, overall and stratified by age (2–5 and 6–10 years), and the immunogenicity and safety of MenACWY-TT administered to all study participants at M68 post-primary vaccination.ResultsAt M68, 33.3% (age group 2–5 years) and 47.1% (age group 6–10 years) of the children vaccinated with MenACWY-TT, and 50.0% (age group 2–5 years) and 75.9% (age group 6–10 years) vaccinated with MenC-CRM₁₉₇ retained titers ≥1:8 for MenC, as assessed by a serum bactericidal assay using rabbit complement (rSBA). In the MenACWY-TT recipients, the percentages of children retaining rSBA titers ≥1:8 for MenA, MenW, and MenY were 81.7%, 47.3% and 66.7% in age group 2–5 years and 91.8%, 58,8% and 76.5% in age group 6–10 years, respectively. The booster dose induced robust responses (100% for all serogroups) and was well-tolerated.ConclusionsAntibody persistence (rSBA titers ≥ 1:8) for serogroups A, W and Y was observed in more than 50.0% of the children 68 M after receiving one dose of MenACWY-TT; for MenC, antibody persistence was observed in more than one third of MenACWY-TT and more than half of MenC-CRM₁₉₇ recipients. Vaccination with a booster dose of MenACWY-TT induced robust immune responses for all serogroups.     

Immunity to hepatitis B persists in adolescents 15–16 years of age vaccinated in infancy with three doses of hepatitis B vaccine

ObjectiveVaccination of infants against hepatitis B virus (HBV) using hepatitis B vaccine is effective in preventing the infection during early childhood and there is a growing evidence of long-term protection. So far, no need for a booster dose has been identified in healthy subjects; however further follow-up continues to determine the exact duration of protection. We evaluated antibody persistence and immune response to a hepatitis B vaccine challenge dose in children aged 15–16 years, previously vaccinated with 3-doses of the same vaccine in infancy (third dose received before 18 months of age).MethodsA single hepatitis B vaccine challenge dose containing 10 μg hepatitis B surface (HBs) antigen was administered to adolescents aged 15–16 years. Blood samples were taken before and one month after the challenge dose to measure anti-HBs antibodies using a chemiluminescence immunoassay. Solicited local and general symptoms, as well as unsolicited and serious adverse events were recorded after the challenge dose.Results303 subjects were enrolled, of whom 302 and 293 subjects formed the total vaccinated and according-to-protocol cohorts, respectively. Pre-challenge, 65.4% (95% CI: 59.6–70.9) subjects were seroprotected (anti-HBs antibody concentration ≥10 mIU/mL). One month post-challenge, 97.9% (95% CI: 95.6–99.2) were seroprotected, while 90.8% (95% CI: 86.8–93.8) had anti-HBs antibody concentrations ≥100 mIU/mL. The post-challenge geometric mean concentration (GMC; 4134.9 [95% CI: 3114.2–5490.1]) was 150-fold higher than the pre-challenge GMC. Overall, 96.9% (95% CI: 94.2–98.6) subjects mounted an anamnestic response. The safety and reactogenicity profile of the hepatitis B vaccine challenge dose was consistent with previous experience.ConclusionsImmunity to hepatitis B persists in 15–16 year old adolescents following primary vaccination in infancy.Trial registrationhttp://www.clinicaltrials.gov NCT01847430.     

Media and public reactions toward vaccination during the ‘hepatitis B vaccine crisis’ in China

BackgroundPublic disputations affected vaccine confidence and vaccine rates particularly when adverse events occur. The vigorous development of Internet in China provides an opportunity to observe public reaction and sentiment toward vaccination when Kangtai Hepatitis B vaccine crisis happened and evolved to a widespread debate on the internet from December 12, 2013 to January 3, 2014.MethodsThis study conducted Internet surveillance by examining three daily indicators including the daily number of relevant online news article, Sina Weibo posts and Baidu search index during the crisis. We also analyzed the sentiments of relevant original microblog posts collected from Sina Weibo platform in the crisis.ResultsA total of 17 infant deaths were reported to associated with Hepatitis B vaccination. Three major waves of high media and public attention were detected. The daily indicators reached their peaks in the second wave after the relevant vaccine was suspended by the authority (from December 20 to December 29, 2013) with 23,200 daily online news reports, 34,018 Sina Weibo posts and 17,832 Baidu search indices. There were significant correlations between the daily amount of online news, Weibo posts, and Baidu searches (p < .001). The contents analysis suggested 1343 out of 1608 (83.5%) original Weibo posts expressed negative sentiment with almost 90% in the second wave.ConclusionThis study found the Kangtai vaccine crisis raised great public attention and negative sentiment toward vaccinations on the internet in China. Policy change such as suspension of the suspected vaccine might trigger even greater reaction and more negative sentiment. The government should provide ways to address emerging public concerns after policy change to avoid misinformation and misunderstanding during such a vaccine crisis.     

Serotype distribution of invasive Streptococcus pneumoniae in adults 65 years of age and over after the introduction of childhood 13-valent pneumococcal conjugate vaccination programs in Canada, 2010–2016

The 13-valent conjugate vaccine (PCV13) was recommended for childhood immunization programs in 2010 in Canada and has decreased the incidence of invasive pneumococcal disease (IPD) in children and changed the epidemiology of IPD in adults. This study investigated the epidemiology of IPD in adults 65 years of age and older in Canada. A total of 7282 invasive S. pneumoniae isolated from adults ≥65 years old were serotyped from 2010 to 2016 and antimicrobial susceptibility was performed on 2527 isolates. Serotyping was performed by Quellung reaction using commercial antisera and antimicrobial susceptibilities were determined by broth microdilution. PCV7 serotypes decreased non-significantly from 2010 to 2016 from 9.1% (n = 96) to 6.7% (n = 72) while the additional six PCV13 serotypes declined significantly from 39.5% (n = 418) to 18.6% (n = 201) (p < 0.05). The 23-valent pneumococcal polysaccharide vaccine (PPV23) and non-vaccine (NVT) serotypes increased from 26.3% (n = 278) to 36.2% (n = 393) (p < 0.05), and from 25.1% (n = 266) to 38.4% (n = 416) (p < 0.05), respectively. There were no significant changes in antimicrobial resistance rates from 2011 to 2016: 24.1% of the IPD from adults ≥65 years were resistant to clarithromycin (n = 609), 10.0% to doxycycline (n = 254), 11.8% to penicillin (n = 299), 5.2% to cefuroxime (n = 131), 6.6% to clindamycin (n = 168), 6.0% to trimethoprim-sulfamethoxazole (n = 152), and 0.5% (n = 12) to ceftriaxone. Although overall incidence of IPD in adults ≥65 years has remained relatively constant from 2010 to 2016, childhood PCV13 vaccination programs have been successful in indirectly reducing IPD caused by PCV13 serotypes in adults through herd immunity effects.