Nationwide Vaccination Research Articles

HPV: Hope in 15 years for unvaccinated women

The deadly cervical cancer-causing human papillomavirus could be eliminated in South Africa within 15 years if ground-breaking new ‘test-and-treat’ technology for women can be successfully introduced to supplement nationwide vaccination of primary schoolgirls.

The effect of mass vaccination campaigns against polio on the utilization of routine immunization services: A regression discontinuity design

BackgroundIn most low and middle-income countries (LMIC), vaccines are primarily distributed by routine immunization services (RI) at health facilities. Additional opportunities for vaccination are also provided through mass vaccination campaigns, conducted periodically as part of disease-specific initiatives. It is unclear whether these campaigns are detrimental to RI services, or wether they may stimulate the utilization of RI. MethodsUnobserved confounders and reverse causality have limited existing evaluations of the effects of mass vaccination campaigns on RI services. We explored the use of a regression discontinuity design (RDD) to measure these effects more precisely. This is a quasi-experimental method, which exploits random variations in birth dates to identify the causal effects of vaccination campaigns. We applied RDD to survey data on a nationwide vaccination campaign against Polio conducted in Bangladesh. ResultsWe compared systematically the children born immediately before vs. after the vaccination campaign. These two groups had similar background characteristics, but differed by their exposure to the vaccination campaign. Contrary to previous studies, exposure to the campaign had positive effects on RI utilization. Children exposed to the campaign received between 0.296 and 0.469 additional doses of DPT vaccine by age 4months than unexposed children. ConclusionsRDD constitutes a promising tool to assess the effects of mass vaccination campaigns on RI services. It could be tested in additional settings, using larger and more precise datasets. It could also be extended to measure the effects of other disease-specific interventions on the functioning of health systems, in particular those that occur at a discrete point in time and/or include age-related eligibility criteria.

The impact of a pneumococcal conjugate vaccination program on the nasopharyngeal carriage, serotype distribution and antimicrobial resistance of Streptococcus pneumoniae among healthy children in Turkey

BackgroundThe 7-valent conjugate pneumococcal vaccine (PCV7) was introduced by the Turkey National Immunization Program in 2008 and replaced by the PCV13 in 2011. We assessed the impact of PCV vaccination on the nasopharyngeal (NP) carriage, serotype distribution and antimicrobial resistance of Streptococcus pneumoniae (SP) among healthy Turkish children. MethodsA prospective surveillance study was performed between September 2011 and September 2013 in Istanbul, Turkey. NP swabs, demographic data, and vaccination statuses were obtained from 2165 healthy children aged 0–18years. Pneumococcal carriage was defined by a positive culture; serotyping was performed via multiplex conventional PCR, and the antibiotic susceptibilities of the isolates were determined based on the minimum inhibitory concentration (MIC) values of the Clinical Laboratory Standards Institute (CLSI). ResultsThe prevalence of pneumococcal carriage was 6.4%. The carriage rates were 8%, 7%, and 5% in the following age groups: 0–24months, 25–60months, and >60months, respectively. The carriage rate was significantly higher in the 0–24month age group than in the >60months age group (p=0.03). Sixty percent of the children were not vaccinated with any PCV; 4%, 2%, and 4% received at least 1, 2 or 3 doses and 30% children received the full schedule (4 doses) of either PCV7 or PCV13. Among the isolated S. pneumoniae strains, 45% were of the non-vaccine type (NVT) and 55% were of the vaccine type (VT). The children who received at least a single PCV dose had significantly lower odds of colonization via VT serotypes than the non-vaccinated children [odds ratio: 0.61 (95% confidence interval=0.41–0.91), p=0.01]. The percentages of the serotypes covered by PCV7 and PCV13 were 51% and 56%, respectively. The most frequently isolated serotypes were 6A/B/C (n=22, 16.5%), 19F (n=18, 13.5%), 23F (n=15, 11.2%), serotype 9V/A (n=10, 7.5%), 12F (n=5, 4.5%), 15A/F (n=7, 4.5%) and 22 A/F (n=6, 4.5%). Using the meningitis criteria and the MIC, 62% of the isolates were resistant to penicillin and 13% were non-sensitive to ceftriaxone. Erythromycin and clindamycin resistance were 43% and 31%, respectively. ConclusionWe shown that following nation-wide PCV vaccination, S. pneumoniae NP carriage was decreased.

Molecular Evolution and Phylodynamics of Acute Hepatitis B Virus in Japan.

Hepatitis B virus (HBV) is prevalent worldwide and causes liver diseases, including acute and chronic hepatitis. Ten HBV genotypes (A–J) with distinct geographic distributions have been reported. Cases of acute HBV infection with genotype A have increased in Japan nationwide since the 1990s, mainly through sexual transmission. To investigate the molecular evolution and phylodynamics of HBV genotypes, we collected acute HBV isolates acquired in Japan from 1992–2002. Full genomes were obtained for comprehensive phylogenetic and phylodynamic analysis, with other Japanese HBV sequences from GenBank that were isolated during 1991–2010. HBV genotypes were classified using the maximum-likelihood and Bayesian methods. The GMRF Bayesian Skyride was used to estimate the evolution and population dynamics of HBV. Four HBV genotypes (A, B, C, and H) were identified, of which C was the major genotype. The phylodynamic results indicated an exponential growth between the 1960s and early 1990s; this was followed by a population bottleneck after 1995, possibly linked with successful implementation of a nationwide vaccination program. However, HBV/A increased from 1990 to 2003–2004, and then started to decrease. The prevalence of genotype A has increased over the past 10 years. Phylodynamic inference clearly demonstrates a steady population growth compatible with an ongoing subepidemic; this might be due to the loss of immunity to HBV in adolescents and people being born before the vaccination program. This is the first phylodynamic study of HBV infection in Japan and will facilitate understanding the molecular epidemiology and long-term evolutionary dynamics of this virus in Japan.

Socioeconomic status and vaccine coverage during wild-type poliovirus emergence in Israel.

In August 2013, a nationwide vaccination campaign with bivalent oral polio vaccine (bOPV) was initiated after isolation of wild-type poliovirus type 1 (WPV-1) in routine sewage surveillance in Israel. The campaign started in the Southern district and later extended to the entire country. This study examined the association between socioeconomic status (SES), and compliance with bOPV vaccine during the campaign. Nationwide data relating to SES by geographical cluster were correlated with vaccine coverage rates in the same areas. All analyses were conducted separately for Jews and Arabs. Coverage with the bOPV vaccination campaign in the Arab population (92·4%) was higher than in the Jewish population (59·2%). This difference was consistently present in all SES clusters. In the Jewish population there was an inverse correlation between SES and vaccination coverage rates (R = -0·93, P < 0·001). Lower vaccination coverage with supplemental vaccine activities in higher SES groups is a challenge that needs to be addressed in future public health events and emergencies in order to achieve satisfactory protection rates for the public.

Cost-utility analysis of a nationwide vaccination programme against serogroup B meningococcal disease in Israel.

Using cost-utility analysis, to evaluate whether or not to adopt a Neisseria meningitidis serogroup B vaccination programme for Israeli children. Epidemiological, demographic, health service utilisation and economic data were integrated into a spreadsheet model to calculate the cost per averted disability-adjusted life year (DALY) of the intervention. Assuming 78% vaccine efficacy with no herd immunity, vaccination will prevent 223 cases and 22 deaths over a 100-year period. Based on vaccine price of $60 per dose, total intervention costs ($315,400,000) are partially offset by a $22,700,000 reduction in treatment and sequelae costs as a result of decreased morbidity. The intervention was not cost-effective since the net cost ($292,700,000) per averted DALY gained (1249 mostly due to decreased mortality) was $234,394. Additional two dose catch-up programmes vaccinating children in cohorts aged 1-2 to 1-13 were also not cost-effective. The vaccination will become cost-effective if vaccine costs fall below $19.44 per dose. However, in identified high risk areas, the vaccine would be cost-effective and could be recommended for use both with and without catch-up campaigns.

Physicians', Nurses', and Medical Assistants' Perceptions of the Human Papillomavirus Vaccine in a Large Integrated Health Care System.

Vaccination against the human papillomavirus (HPV) decreases risks of cancer and genital warts and the need for gynecologic procedures, yet nationwide vaccination rates are low. Previous surveys exploring this phenomenon have not included input from nurses and medical assistants, who play integral roles in HPV vaccine delivery. To understand perceptions of HPV vaccine delivery among physicians, nurses, and medical assistants in a large integrated health care system in Southern California. Online surveys were sent to 13 nurse administrators and 75 physicians. Physicians were instructed to forward the survey to nurses and medical assistants with whom they work. A total of 76 surveys were completed, consisting of 52 physicians, 16 clinical nurses and medical assistants, and 8 nurse administrators. Physicians' perceptions of vaccine safety or strength of recommendation did not differ by specialty department. Physicians reportedly perceived the HPV vaccine as safer than did clinical nurses and medical assistants (p < 0.001), who indicated they wanted more education on the safety and efficacy of the vaccine before being comfortable strongly recommending it. Respondents advised that all clinicians could improve in their roles as HPV vaccine advocates through patient counseling and providing informational literature and that workflow standardization was needed to minimize missed vaccination opportunities. Physicians reportedly perceive the HPV vaccine as safer compared with nurses and medical assistants. Both groups think that more education of nonphysician staff is needed. Having proper systems in place is also vital to improving vaccination compliance.

Viral Hepatitis in Cambodia: Past, Present, and Future.

ABSTRACTThe prevalence of viral hepatitis represents Cambodia as 1 of the highest endemic countries in the world. But the prevalence of viral hepatitis B among 5-year-olds is on a decreasing trend due to the effect of nationwide vaccination against hepatitis B. There are key interventions to address viral hepatitis by the Cambodian Ministry of Health. There are so far no comprehensive national guidelines for the prevention, care, and treatment of viral hepatitis.In 2014, the coverage of hepatitis B vaccine at birth and HepB3 vaccine was very high, at 87 and 97% respectively. Other interventions include the screening of viral hepatitis B and C among blood donors; the enhancement of infection prevention and control at health facilities; the program for People Who Use Drugs (PWUDs) and People Who Inject Drugs (PWIDs); control and prevention of HIV/AIDS and sexually transmitted diseases (STDs); and improved sanitation, clean water, and food safety.The diagnosis of viral hepatitis B and C could be made only at the national and provincial referral hospitals and there are no specific antiviral therapies for people who are infected with hepatitis B and C.How to cite this articleSreng B, Sophal C, Srun S, Samnang C, Huot E. Viral Hepatitis in Cambodia: Past, Present, and Future. Euroasian J Hepato-Gastroenterol 2016;6(1):45-48.

Is Hiding Foot and Mouth Disease Sensitive Behavior for Farmers? A Survey Study in Sri Lanka.

Foot and mouth disease (FMD) has a long history in Sri Lanka and was found to be endemic in various parts of the country and constitutes a constant threat to farmers. In Sri Lanka, currently there is no regular, nationwide vaccination programme devised to control FMD. Therefore, improving farmers’ knowledge regarding distinguishing FMD from other diseases and ensuring prompt reporting of any suspicion of FMD as well as restricting movement of animals are critical activities for an effective FMD response effort. Therefore, the main purpose of this study was to clarify the relationship between farmers’ knowledge levels and their behaviors to establish a strategy to control FMD. In our study, item count technique was applied to estimate the number of farmers that under-report and sell FMD-infected animals, although to do so is prohibited by law. The following findings were observed: about 63% of farmers have very poor knowledge of routes of FMD transmission; ‘under-reporting’ was found to be a sensitive behavior and nearly 23% of the farmers were reluctant to report FMD-infected animals; and ‘selling FMD-infected animals’ is a sensitive behavior among high-level knowledge group while it is a non-sensitive behavior among the low-level knowledge group. If farmers would understand the importance of prompt reporting, they may report any suspected cases of FMD to veterinary officials. However, even if farmers report honestly, they do not want to cull FMD-infected animals. Thus, education programs should be conducted not only on FMD introduction and transmission, but also its impact. Furthermore, consumers may criticize the farmers for culling their infected animals. Hence, not only farmers, but also consumers need to be educated on the economic impact of FMD and the importance of controlling an outbreak. If farmers have a high knowledge of FMD transmission, they consider selling FMD-infected animals as a sensitive behavior. Therefore, severe punishment should be levied for selling FMD-infected animals.

A simple model to quantitatively account for periodic outbreaks of the measles in the Dutch Bible Belt

In the Netherlands there has been nationwide vaccination against the measles since 1976. However, in small clustered communities of orthodox Protestants there is widespread refusal of the vaccine. After 1976, three large outbreaks with about 3000 reported cases of the measles have occurred among these orthodox Protestants. The outbreaks appear to occur about every twelve years. We show how a simple Kermack-McKendrick-like model can quantitatively account for the periodic outbreaks. Approximate analytic formulae to connect the period, size, and outbreak duration are derived. With an enhanced model we take the latency period in account. We also expand the model to follow how different age groups are affected. Like other researchers using other methods, we conclude that large scale underreporting of the disease must occur.

Estimating influenza vaccine effectiveness using routine surveillance data among children aged 6–59 months for five consecutive influenza seasons

We aimed to estimate the pooled vaccine effectiveness (VE) in children over five winters through data linkage of two existing surveillance systems. Five test-negative case-control studies were conducted from November to February during the 2004/2005 to 2008/2009 seasons. Sentinel physicians from the Viral Surveillance Network enrolled children aged 6-59 months with influenza-like illness to collect throat swabs. Through linking with a nationwide vaccination registry, we measured the VE with a logistic regression model adjusting for age, gender, and week of symptom onset. Both fixed-effects and random-effects models were used in the meta-analysis. Four thousand four hundred and ninety-four subjects were included. The proportion of influenza test-positive subjects across the five seasons was 11.5% (132/1151), 7.2% (41/572), 23.9% (189/791), 6.6% (75/1135), and 11.2% (95/845), respectively. The pooled VE was 62% (95% confidence interval (CI) 48-83%) in both meta-analysis models. By age category, VE was 51% (95% CI 23-68%) for those aged 6-23 months and 75% (95% CI 60-84%) for those aged 24-59 months. Influenza vaccination provided measurable protection against laboratory-confirmed influenza among children aged 6-59 months despite variations in the vaccine match during the 2004/2005 to 2008/2009 influenza seasons in Taiwan.

Estimated public health impact of nationwide vaccination of infants with 7-valent pneumococcal conjugate vaccine (PCV7) in China

The goal of this study was to provide a comprehensive analysis of the potential health impact of universal vaccination of infants with the 7-valent pneumococcal conjugate vaccine (PCV7) in China. A decision-analytic model designed for pneumococcal disease and outcomes of pneumococcal infection was populated with local age-specific incidence and mortality data to estimate the expected health benefits of vaccinating birth cohorts of approximately 16 million infants per year over a 10-year time horizon in China. The model incorporates both the direct impact on vaccinated children and the indirect effect of herd protection on unvaccinated children and adults. The model predicts that more than 16.2 million cases of pneumococcal disease and 709 411 deaths could be prevented in China over the initial 10-year period following the introduction of the PCV7 vaccine. The majority of these health benefits are due to the indirect effectiveness of the vaccine on the unvaccinated population, resulting in approximately 10.8 million cases prevented and 636 371 lives saved over 10 years. The results suggest that a policy of universal PCV7 vaccination among infants in China would have a substantial positive public health impact on the population of China.

Evaluation of abdominal ultrasonography mass screening for hepatocellular carcinoma in Taiwan

Mass screening with abdominal ultrasonography (AUS) has been suggested as a tool to control adult hepatocellular carcinoma (HCC) in individuals, but its efficacy in reducing HCC mortality has never been demonstrated. This study aimed to assess the effectiveness of reducing HCC mortality by mass AUS screening for HCC based on a program designed and implemented in the Changhua Community-based Integrated Screening (CHCIS) program with an efficient invitation scheme guided by the risk score. We invited 11,114 (27.0%) of 41,219 eligible Taiwanese subjects between 45 and 69 years of age who resided in an HCC high-incidence area to attend a risk score-guided mass AUS screening between 2008 and 2010. The efficacy of reducing HCC mortality was estimated. Of the 8,962 AUS screening attendees (with an 80.6% attendance rate), a total of 16 confirmed HCC cases were identified through community-based ultrasonography screening. Among the 16 screen-detected HCC cases, only two died from HCC, indicating a favorable survival. The cumulative mortality due to HCC (per 100,000) was considerably lower in the invited AUS group (17.26) compared with the uninvited AUS group (42.87) and the historical control group (47.51), yielding age- and gender-adjusted relative mortality rates of 0.69 (95% confidence interval [CI]: 0.56-0.84) and 0.63 (95% CI: 0.52-0.77), respectively. Conclusion: The residents invited to community-based AUS screening for HCC, compared with those who were not invited, showed a reduction in HCC mortality by ∼31% among subjects aged 45-69 years who had not been included in the nationwide vaccination program against hepatitis B virus infection. (Hepatology 2014;59:1840–1849)

Efficacy and effectiveness of infant vaccination against chronic hepatitis B in the Gambia Hepatitis Intervention Study (1986–90) and in the nationwide immunisation program

BackgroundGambian infants were not routinely vaccinated against hepatitis B virus (HBV) before 1986. During 1986–90 the Gambia Hepatitis Intervention Study (GHIS) allocated 125,000 infants, by area, to vaccination or not and thereafter all infants were offered the vaccine through the nationwide immunisation programme. We report HBV serology from samples of GHIS vaccinees and unvaccinated controls, and from children born later.MethodsDuring 2007–08, 2670 young adults born during the GHIS (1986-90) were recruited from 80 randomly selected villages and four townships. Only 28% (753/2670) could be definitively linked to their infant HBV vaccination records (255 fully vaccinated, 23 partially vaccinated [1–2 doses], 475 not vaccinated). All were tested for current HBV infection (HBV surface antigen [HBsAg]) and, if HBsAg-negative, evidence of past infection (HBV core-protein antibody [anti-HBc]). HBsAg-positive samples (each with two age- and sex-matched HBsAg-negative samples) underwent liver function tests. In addition, 4613 children born since nationwide vaccination (in 1990-2007) were tested for HBsAg. Statistical analyses ignore clustering.ResultsComparing fully vaccinated vs unvaccinated GHIS participants, current HBV infection was 0.8% (2/255) vs 12.4% (59/475), p < 0.0001, suggesting 94% (95% CI 77-99%) vaccine efficacy. Among unvaccinated individuals, the prevalence was higher in males (p = 0.015) and in rural areas (p = 0.009), but adjustment for this did not affect estimated vaccine efficacy. Comparing fully vaccinated vs unvaccinated participants, anti-HBc was 27.4% (70/255) vs 56.0% (267/475), p < 0.00001. Chronic active hepatitis was not common: the proportion of HBsAg-positive subjects with abnormal liver function tests (ALT > 2 ULN) was 4.1%, compared with 0.2% in those HBsAg-negative. The prevalence of antibodies to hepatitis C virus was low (0.5%, 13/2592). In children born after the end of GHIS, HBsAg prevalence has remained low; 1.4% (15/1103) in those born between 1990–97, and 0.3% (9/35150) in those born between 1998–2007.ConclusionsInfant HBV vaccination achieves substantial protection against chronic carriage in early adulthood, even though approximately a quarter of vaccinated young adults have been infected. This protection persists past the potential onset of sexual activity, reinforcing previous GHIS findings of protection during childhood and suggesting no need for a booster dose. Nationwide infant HBV vaccination is controlling chronic infection remarkably effectively.

Entecavir in Severe Acute Hepatitis B

An estimated 350 million persons worldwide are chronically infected with HBV [1]. The average estimated carrier rate of Hepatitis B Virus (HBV) in India is 4%, with a total pool of approximately 36 million carriers. Most of India’s carrier pool is established in early childhood, predominantly by horizontal spread due to crowded living conditions and poor hygiene. Acute and subacute liver failure is common complications of viral hepatitis in India and HBV is reckoned to be the etiological agent in 42% and 45% of adult cases, respectively. In conclusion, hepatitis B is a major public health problem in India and will continue to be until appropriate nationwide vaccination programmes and other control measures are established.

Preinvasive Lesions in Gynaecology – Uterine Cervix

Preinvasive lesion of the uterine cervix can give rise to cervical cancer. High-risk human papillomaviruses with high oncogenic potential are considered to be the main etiopathological factors with interaction of other risk factors (recurrent inflammation of the cervix, injury of the cervix, immunosuppressive conditions, sexual promiscuity, etc.). Early dia-gnosis of these changes at regular gynecological examinations and adequate treatment can prevent of malignant transformation. Organized cervical screening and implementation of nationwide vaccination against human papillomavirus promises to reduce the incidence of cervical cancer.

Diarrhoea-related hospitalizations in children before and after implementation of monovalent rotavirus vaccination in Mexico

To assess, by socioeconomic setting, the effect of nationwide vaccination against species A rotavirus (RVA) on childhood diarrhoea-related hospitalizations in Mexico. Data on children younger than 5 years who were hospitalized for diarrhoea in health ministry hospitals between 1 January 2003 and 31 December 2011 were collected from monthly discharge reports. Human development indexes were used to categorize the states where hospitals were located as having generally high, intermediate or low socioeconomic status. Annual rates of hospitalization for diarrhoea--per 10,000 hospitalizations for any cause--were calculated. Administrative data were used to estimate vaccine coverage. In the states with high, intermediate and low socioeconomic status, coverage with a two-dose monovalent RVA vaccine--among children younger than 5 years--had reached 93%, 86% and 71%, respectively, by 2010. The corresponding median annual rates of hospitalization for diarrhoea--per 10,000 admissions--fell from 1001, 834 and 1033 in the "prevaccine" period of 2003-2006, to 597, 497 and 705 in the "postvaccine" period from 2008 to 2011, respectively. These decreases correspond to rate reductions of 40% (95% confidence interval, CI: 38-43), 41% (95% CI: 38-43) and 32% (95% CI: 29-34), respectively. Nationwide, RVA vaccination appeared to have averted approximately 16,500 hospitalizations for childhood diarrhoea in each year of the postvaccine period. Monovalent RVA vaccination has substantially reduced childhood diarrhoea-related hospitalizations for four continuous years in discretely different socioeconomic populations across Mexico.

Survey of Asian Patients with Hepatitis B Infection: Limited Knowledge of Transmission and Screening of Family Members

Asian American families are disproportionately affected by Hepatitis B (HBV) infection. We aimed to assess the extent of screening family members of Asian patients with known HBV infection as well as patients' knowledge of HBV disease. A cross-sectional survey of established Asian patients with HBV-infection was performed at a university liver clinic. Outcome measures included the percentage of family members whose HBV serostatus was unknown and the percentage of patients who were able to correctly identify modes of transmission. A total of 803 US-based family members were identified by 58 patients. Patients did not know the HBV serostatus of 50% of their family members and 28% of their immediate family members. Fifty percent of participants did not know how they had acquired HBV or stated unlikely transmission modes. Though nationwide vaccination campaigns target this underrepresented population, screening family members of Asian patients with HBV remains a challenge.

PRM85 - Estimated public health impact of nationwide vaccination of infants with 7-valent pneumococcal conjugate vaccine (pcv7) in China

PRM85 - Estimated public health impact of nationwide vaccination of infants with 7-valent pneumococcal conjugate vaccine (pcv7) in China

Modelling the effect of vaccination on the Meningococcal B epidemic in New Zealand

A nation-wide vaccination campaign began in New Zealand in 2004 with the aim of stopping the epidemic of meningococcal B disease. Approximately 80% of those under 20 years of age when the campaign was launched were vaccinated with three doses of a tailor-made vaccine. We propose a framework for a mathematical model based on the susceptible–carrier–infectious–removed (SCIR) structure. We show how the model could be used to calculate the predicted yearly incidence of infection in the absence of vaccination, and compare this to the effect that vaccination had on the course of the epidemic. Our model shows that vaccination led to a considerable decrease in the incidence of infection compared to what would have been seen otherwise. We then use our model to explore the potential effect of alternative vaccination schemes, and show that the one that was implemented was the best of all the possibilities we consider. doi:10.1017/S1446181113000047