Doses Of Poliovirus Vaccine Research Articles

Immunogenicity of Two Fractional Inactivated Poliovirus Vaccine Doses vs Single Intramuscular Inactivated Poliovirus Vaccine Dose in Infants of Low- and Middle-income Countries: A Prospective Case-control Study

Immunogenicity of Two Fractional Inactivated Poliovirus Vaccine Doses vs Single Intramuscular Inactivated Poliovirus Vaccine Dose in Infants of Low- and Middle-income Countries: A Prospective Case-control Study

Progress Toward Poliomyelitis Eradication - Afghanistan, January 2022-June 2023.

When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was reported in 125 countries. Since 2017, Afghanistan and Pakistan remain the only countries with uninterrupted endemic WPV type 1 (WPV1) transmission. This report describes activities and progress toward polio eradication in Afghanistan during January 2022-June 2023. Two WPV1 cases were reported during January-December 2022 and five during January-June 2023 (as of August 26), all from three provinces in the southeast and east regions bordering Pakistan. All five 2023 patients had reportedly received ≥16 oral poliovirus vaccine doses. WPV1 was detected in sewage samples from a site in the south region in May 2023 and one in the north region in June 2023, the first detections since February 2021 and March 2020, respectively. Restrictions on house-to-house vaccination limit the effectiveness of vaccination campaigns in parts of the south and northeast regions. Because of population movement, the risk for transmission in Afghanistan and Pakistan will remain if WPV1 circulation continues in either country. Despite operational improvements in vaccination activities, interruption of WPV1 transmission in Afghanistan will require committed, uninterrupted efforts, including ongoing coordination with Pakistan on polio eradication activities, to address vaccination coverage gaps that sustain WPV1 circulation.

Immuno-persistence of the different primary polio vaccine schedules and immunogenicity of the booster dose by sabin inactivated or bivalent oral poliovirus vaccine in children aged 4 years: an open-label, randomised, controlled phase 4 trial in China

Sabin inactivated and bivalent oral poliovirus vaccine (sIPV, bOPV) were commonly used in China since 2016. We conducted an open-label, randomised, controlled phase 4 trial to assess immune persistence following sequential immunisation with sIPV or bOPV, and immunogenicity and safety of a booster dose of poliovirus vaccine in children aged 4 years. Participants from a previous clinical trial with three different sequential schedules with sIPV (I) or bOPV (B) at ages 2, 3, and 4 months (Groups I-B-B, I-I-B, I-I-I) in 2017 were followed-up. The children were further divided into five subgroups after sIPV was given for Group I-B-B, and sIPV or bOPV randomly given for Group I-I-B and Group I-I-I (128 children in Groups I-B-B-I, 60 in Group I-I-B-B, 64 in Group I-I-B-I, 68 in Group I-I-I-B, 67 in Group I-I-I-I). Immune persistence and immunogenicity were assessed by measuring poliovirus type-specific antibodies, and safety were analysed in all children who received the booster dose. Between Dec 5, 2020 and Jun 30, 2021, we respectively enrolled 381 participants in the immune persistence analysis, and 352 participants in per protocol (PP) analysis of the immunogenicity of the booster immunisation. Seropositivity rates of antibodies against poliovirus types 1 and 3 were all >90% four years after primary immunisation, while for poliovirus type 2 were 46.83%, 75.41%, and 90.23% (χ2=60.948, P<0.001) for Groups I-B-B, I-I-B, and I-I-I, respectively. After the booster dose, seropositivity rates were 100% for all three serotypes in Group I-B-B-I, I-I-B-I and I-I-I-I; In Group I-I-B-B and I-I-I-B, the seropositivity rates for types 1 and 3 were all 100%, for type 2 were 92.59% and 98.46%. The geometric mean titres (GMTs) against poliovirus 1 and 3 were all high in five groups (>1860.73), and the GMTs against type 2 were significantly lower in groups booster with bOPV: Group I-I-B-B (50.60) and Group I-I-I-B (247.84). There was no significant difference in seropositivity rates or GMTs for all three serotypes (P>0.05) between Group I-I-B-I and I-I-I-I. No serious adverse events occurred during the study. Our findings suggest that at least two sIPV doses are needed in the current routine poliovirus immunisation schedule, and schedules containing 3 or 4 doses of sIPV provide better protection against poliovirus type 2 than the current sIPV-sIPV-bOPV-bOPV schedule in China. Medical and Health Science and Technology of Zhejiang Province (2021KY118). This trial was registered with ClinicalTrials.gov (NCT04576910).

Cases of Acute Flaccid Paralysis Associated with Coxsackievirus A2: Findings of a 20-Year Surveillance in the Russian Federation.

Surveillance for acute flaccid paralysis syndrome (AFP) in children under 15 is the backbone of the Global Polio Eradication Initiative. Laboratory examination of stool samples from AFP cases allows the detection of, along with polioviruses, a variety of non-polio enteroviruses (NPEV). The etiological significance of these viruses in the occurrence of AFP cases has been definitively established only for enteroviruses A71 and D68. Enterovirus Coxsackie A2 (CVA2) is most often associated with vesicular pharyngitis and hand, foot and mouth disease. Among 7280 AFP cases registered in Russia over 20 years (2001–2020), CVA2 was isolated only from five cases. However, these included three children aged 3 to 4 years, without overt immune deficiency, immunized with 4–5 doses of poliovirus vaccine in accordance with the National Vaccination Schedule. The disease resulted in persistent residual paralysis. Clinical and laboratory data corresponded to poliomyelitis developing during poliovirus infection. These findings are compatible with CVA2 being the cause of AFP. Molecular analysis of CVA2 from these patients and a number of AFP cases in other countries did not reveal association with a specific phylogenetic group, suggesting that virus genetics is unlikely to explain the pathogenic profile. The overall results highlight the value of AFP surveillance not just for polio control but for studies of uncommon AFP agents.

Vaccination Coverage by Age 24 Months Among Children Born in 2017 and 2018 - National Immunization Survey-Child, United States, 2018-2020.

Immunization is a safe and cost-effective means of preventing illness in young children and interrupting disease transmission within the community.* The Advisory Committee on Immunization Practices (ACIP) recommends vaccination of children against 14 diseases during the first 24 months of life (1). CDC uses National Immunization Survey-Child (NIS-Child) data to monitor routine coverage with ACIP-recommended vaccines in the United States at the national, regional, state, territorial, and selected local levels.† CDC assessed vaccination coverage by age 24 months among children born in 2017 and 2018, with comparisons to children born in 2015 and 2016. Nationally, coverage was highest for ≥3 doses of poliovirus vaccine (92.7%); ≥3 doses of hepatitis B vaccine (HepB) (91.9%); ≥1 dose of measles, mumps, and rubella vaccine (MMR) (91.6%); and ≥1 dose of varicella vaccine (VAR) (90.9%). Coverage was lowest for ≥2 doses of influenza vaccine (60.6%). Coverage among children born in 2017-2018 was 2.1-4.5 percentage points higher than it was among those born in 2015-2016 for rotavirus vaccine, ≥1 dose of hepatitis A vaccine (HepA), the HepB birth dose, and ≥2 doses of influenza vaccine. Only 1.0% of children had received no vaccinations by age 24 months. Disparities in coverage were seen for race/ethnicity, poverty status, and health insurance status. Coverage with most vaccines was lower among children who were not privately insured. The largest disparities between insurance categories were among uninsured children, especially for ≥2 doses of influenza vaccine, the combined 7-vaccine series, § and rotavirus vaccination. Reported estimates reflect vaccination opportunities that mostly occurred before disruptions resulting from the COVID-19 pandemic. Extra efforts are needed to ensure that children who missed vaccinations, including those attributable to the COVID-19 pandemic, receive them as soon as possible to maintain protection against vaccine-preventable illnesses.

Vaccination Coverage by Age 24 Months Among Children Born in 2016 and 2017 — National Immunization Survey-Child, United States, 2017–2019

Immunization has been described as a "global health and development success story," and worldwide is estimated to prevent 2-3 million deaths annually.* In the United States, the Advisory Committee on Immunization Practices (ACIP) currently recommends vaccination against 14 potentially serious illnesses by the time a child reaches age 24 months (1). CDC monitors coverage with ACIP-recommended vaccines through the National Immunization Survey-Child (NIS-Child); data from the survey were used to estimate vaccination coverage at the national, regional, state, territorial, and selected local area levels† among children born in 2016 and 2017. National coverage by age 24 months was ≥90% for ≥3 doses of poliovirus vaccine, ≥3 doses of hepatitis B vaccine (HepB), and ≥1 dose of varicella vaccine (VAR); national coverage was ≥90% for ≥1 dose of measles, mumps, and rubella vaccine (MMR), although MMR coverage was <90% in 14 states. Coverage with ≥2 doses of influenza vaccine was higher for children born during 2016-2017 (58.1%) than for those born during 2014-2015 (53.8%) but was the lowest among all vaccines studied. Only 1.2% of children had received no vaccinations by age 24 months. Vaccination coverage among children enrolled in Medicaid or with no health insurance was lower than that among children who were privately insured. The prevalence of being completely unvaccinated was highest among uninsured children (4.1%), lower among those enrolled in Medicaid (1.3%), and lowest among those with private insurance (0.8%). The largest disparities on the basis of health insurance status occurred for ≥2 doses of influenza vaccine and for completion of the rotavirus vaccination series. Considering the disruptions to health care provider operations caused by the coronavirus disease 2019 (COVID-19) pandemic, extra effort will be required to achieve and maintain high levels of coverage with routine childhood vaccinations. Providers, health care entities, and public health authorities can communicate with families about how children can be vaccinated safely during the pandemic, remind parents of vaccinations that are due for their children, and provide all recommended vaccinations to children during clinic visits. This will be especially important for 2020-21 seasonal influenza vaccination to mitigate the effect of two potentially serious respiratory viruses circulating in the community simultaneously.

Vaccination Coverage by Age 24 Months Among Children Born in 2015 and 2016 - National Immunization Survey-Child, United States, 2016-2018.

The Advisory Committee on Immunization Practices (ACIP) recommends that children be vaccinated against 14 potentially serious illnesses during the first 24 months of life (1). CDC used data from the National Immunization Survey-Child (NIS-Child) to assess vaccination coverage with the recommended number of doses of each vaccine at the national, state, territorial, and selected local levels* among children born in 2015 and 2016. Coverage by age 24 months was at least 90% nationally for ≥3 doses of poliovirus vaccine, ≥1 dose of measles, mumps, and rubella vaccine (MMR), ≥3 doses of hepatitis B vaccine (HepB), and ≥1 dose of varicella vaccine, although MMR coverage was <90% in 20 states. Children were least likely to be up to date by age 24 months with ≥2 doses of influenza vaccine (56.6%). Only 1.3% of children born in 2015 and 2016 had received no vaccinations by the second birthday. Coverage was lower for uninsured children and for children insured by Medicaid than for those with private health insurance. Vaccination coverage can be increased by improving access to vaccine providers and eliminating missed opportunities to vaccinate children during health care visits. Increased use of local vaccination coverage data is needed to identify communities at higher risk for outbreaks of measles and other vaccine-preventable diseases.

Vaccination Coverage Among Children Aged 19-35 Months - United States, 2016.

Vaccination is the most effective intervention to reduce morbidity and mortality from vaccine-preventable diseases in young children (1). Data from the 2016 National Immunization Survey-Child (NIS-Child) were used to assess coverage with recommended vaccines (2) among children aged 19-35 months in the United States. Coverage remained ≥90% for ≥3 doses of poliovirus vaccine (91.9%), ≥1 dose of measles, mumps, and rubella vaccine (MMR) (91.1%), ≥1 dose of varicella vaccine (90.6%), and ≥3 doses of hepatitis B vaccine (HepB) (90.5%). Coverage in 2016 was approximately 1-2 percentage points lower than in 2015 for ≥3 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP), ≥3 doses of poliovirus vaccine, the primary Haemophilus influenzae type b (Hib) series, ≥3 HepB doses, and ≥3 and ≥4 doses of pneumococcal conjugate vaccine (PCV), with no changes for other vaccines. More direct evaluation of trends by month and year of birth (3) found no change in coverage by age 2 years among children included in combined data from the 2015 and 2016 NIS-Child (born January 2012 through January 2015). The observed decreases in annual estimates might result from random differences in vaccination coverage by age 19 months between children sampled in 2016 and those sampled in 2015, among those birth cohorts eligible to be sampled in both survey years. For most vaccines, 2016 coverage was lower among non-Hispanic black* (black) children than among non-Hispanic white (white) children, and for children living below the federal poverty level† compared with those living at or above the poverty level. Vaccination coverage was generally lower among children insured by Medicaid (2.5-12.0 percentage points), and was much lower among uninsured children (12.4-24.9 percentage points), than among children with private insurance. The Vaccines for Children§ (VFC) program was designed to increase access to vaccines among children who might not otherwise be vaccinated because of inability to pay. Greater awareness and facilitating use of VFC might be helpful in reducing these disparities. Efforts should also be focused on minimizing breaks in continuity of health insurance and eliminating missed opportunities to vaccinate children during visits to health care providers. Despite the observed disparities and small changes in coverage from 2015, vaccination coverage among children aged 19-35 months remained high and stable in 2016.

Routine Vaccination Coverage in Northern Nigeria: Results from 40 District-Level Cluster Surveys, 2014-2015.

BackgroundDespite recent success towards controlling poliovirus transmission, Nigeria has struggled to achieve uniformly high routine vaccination coverage. A lack of reliable vaccination coverage data at the operational level makes it challenging to target program improvement. To reliably estimate vaccination coverage, we conducted district-level vaccine coverage surveys using a pre-existing infrastructure of polio technical staff in northern Nigeria.MethodsHousehold-level cluster surveys were conducted in 40 polio high risk districts of Nigeria during 2014–2015. Global positioning system technology and intensive supervision by a pool of qualified technical staff were used to ensure high survey quality. Vaccination status of children aged 12–23 months was documented based on vaccination card or caretaker’s recall. District-level coverage estimates were calculated using survey methods.ResultsData from 7,815 children across 40 districts were analyzed. District-level coverage with the third dose of diphtheria-pertussis-tetanus vaccine (DPT3) ranged widely from 1–63%, with all districts having DPT3 coverage below the target of 80%. Median coverage across all districts for each of eight vaccine doses (1 Bacille Calmette-Guérin dose, 3 DPT doses, 3 oral poliovirus vaccine doses, and 1 measles vaccine dose) was <50%. DPT3 coverage by survey was substantially lower (range: 28%–139%) than the 2013 administrative coverage reported among children aged <12 months. Common reported reasons for non-vaccination included lack of knowledge about vaccines and vaccination services (50%) and factors related to access to routine immunization services (15%).ConclusionsSurvey results highlighted vaccine coverage gaps that were systematically underestimated by administrative reporting across 40 polio high risk districts in northern Nigeria. Given the limitations of administrative coverage data, our approach to conducting quality district-level coverage surveys and providing data to assess and remediate issues contributing to poor vaccination coverage could serve as an example in countries with sub-optimal vaccination coverage, similar to Nigeria.

Vaccination Coverage Among Children Aged 19-35 Months - United States, 2015.

Sustained high coverage with recommended vaccinations among children has kept many vaccine-preventable diseases at low levels in the United States (1). To assess coverage with vaccinations recommended for children by age 2 years in the United States (2), CDC analyzed data collected by the 2015 National Immunization Survey (NIS) for children aged 19-35 months (born January 2012-May 2014). Overall, coverage did not change during 2014-2015. Coverage in 2015 was highest for ≥3 doses of poliovirus vaccine (93.7%), ≥3 doses of hepatitis B vaccine (HepB) (92.6%), ≥1 dose of measles, mumps, and rubella vaccine (MMR) (91.9%), and ≥1 dose of varicella vaccine (91.8%). The data were also examined for potential vaccination coverage differences by race/ethnicity, poverty status, and urbanicity. Although disparities were noted for each of these factors, the most striking differences were seen for poverty status. Children living below the federal poverty level* had lower coverage with most of the vaccinations assessed compared with children living at or above the poverty level; the largest disparities were for rotavirus vaccine (66.8% versus 76.8%), ≥4 doses of pneumococcal conjugate vaccine (PCV) (78.9% versus 87.2%), the full series of Haemophilus influenzae type b vaccine (Hib) (78.1% versus 85.5%), and ≥4 doses of diphtheria, tetanus, and acellular pertussis vaccine (DTaP) (80.2% versus 87.1%). Although coverage was high in some groups, opportunities exist to continue to address disparities. Implementation of evidence-based interventions, including strategies to enhance access to vaccination services and systems strategies that can reduce missed opportunities, has the potential to increase vaccination coverage for children living below the poverty level and in rural areas (3).

Poliovirus seroprevalence before and after interruption of poliovirus transmission in Kano State, Nigeria

IntroductionIn September 2015, Nigeria was removed from the list of polio-endemic countries after more than 12months had passed since the detection of last wild poliovirus case in the country on 24 July 2014. We are presenting here a report of two polio seroprevalence surveys conducted in September 2013 and October 2014, respectively, in the Kano state of northern Nigeria. MethodsHealth facility based seroprevalence surveys were undertaken at Murtala Mohammad Specialist Hospital, Kano. Parents or guardians of children aged 6–9months, 36–47months, 5–9years and 10–14years in 2013 and 6–9months and 19–22months (corresponding to 6–9months range at the time of 2013 survey) in 2014 presenting to the outpatient department, were approached for participation, screened for eligibility and asked to provide informed consent. A questionnaire was administered and a blood sample collected for polio neutralization assay. ResultsAmong subjects aged 6–9months in the 2013 survey, seroprevalence was 58% (95% confidence interval [CI] 51–66%) to poliovirus type 1, 42% (95% CI 34–50%) to poliovirus type 2, and 52% (95% CI 44–60%) to poliovirus type 3. Among children 36–47months and older, seroprevalence was 85% or higher for all three serotypes. In 2014, seroprevalence in 6–9month infants was 72% (95% CI 65–79%) for type 1, 59% (95% CI 52–66%) for type 2, and 65% (95% CI 57–72%) for type 3 and in 19–22months, 80% (95% CI 74–85%), 57% (49–63%) and 78% (71–83%) respectively. Seroprevalence was positively associated with history of increasing oral poliovirus vaccine doses. ConclusionsThere was significant improvement in seroprevalence in 2014 over the 2013 levels indicating a positive impact of recent programmatic interventions. However the continued low seroprevalence in 6–9month age is a concern and calls for improved immunization efforts to sustain the polio-free Nigeria.

Vaccination Coverage Disparities Between Foreign-Born and U.S.-Born Children Aged 19-35Months, United States, 2010-2012.

Healthy People 2020 targets high vaccination coverage among children. Although reductions in coverage disparities by race/ethnicity have been described, data by nativity are limited. The National Immunization Survey is a random-digit-dialed telephone survey that estimates vaccination coverage among U.S. children aged 19-35months. We assessed coverage among 52,441 children from pooled 2010-2012 data for individual vaccines and the combined 4:3:1:3*:3:1:4 series (which includes ≥4 doses of diphtheria, tetanus, and acellular pertussis vaccine/diphtheria and tetanus toxoids vaccine/diphtheria, tetanus toxoids, and pertussis vaccine, ≥3 doses of poliovirus vaccine, ≥1 dose of measles-containing vaccine, ≥3 or ≥4 doses of Haemophilus influenzae type b vaccine (depending on product type of vaccine; denoted as 3* in the series name), ≥3 doses of hepatitis B vaccine, ≥1 dose of varicella vaccine, and ≥4 doses of pneumococcal conjugate vaccine). Coverage estimates controlling for sociodemographic factors and multivariable logistic regression modeling for 4:3:1:3*:3:1:4 series completion are presented. Significantly lower coverage among foreign-born children was detected for DTaP, hepatitis A, hepatitis B, Hib, pneumococcal conjugate, and rotavirus vaccines, and for the combined series. Series completion disparities persisted after control for demographic, access-to-care, poverty, and language effects. Substantial and potentially widening disparities in vaccination coverage exist among foreign-born children. Improved immunization strategies targeting this population and continued vaccination coverage monitoring by nativity are needed.

Effect of booster doses of poliovirus vaccine in previously vaccinated children, Clinical Trial Results 2013

BackgroundConsidering the current polio situation Pakistan needs vaccine combinations to reach maximum population level immunity. The trial assessed whether inactivated poliovirus vaccine (IPV) can be used to rapidly boost immunity among children in Pakistan. MethodsA five-arm randomized clinical trial was conducted among children (6–24months, 5–6years and 10–11years). Children were randomized in four intervention arms as per the vaccines they received (bOPV, IPV, bOPV+vitamin A, and bOPV+IPV) and a control arm which did not receive any vaccine. Baseline seroprevalence of poliovirus antibodies and serological immune response 28days after intervention were assessed. ResultsThe baseline seroprevalence was high for all serotypes and the three age groups [PV1: 97%, 100%, 96%, PV2: 86%, 100%, 99%, PV3: 83%, 95%, 87% for the three age groups respectively]. There was significantly higher rate of immune response observed in the study arms which included IPV (95–99%) compared with bOPV only arms (11–43%), [p<0.001]; Vitamin A was not associated with improved immune response. Immune response rates in the IPV only arm and IPV+bOPV arm were similar [p>0.5]. ConclusionIPV has shown the ability to efficiently close existing immunity gaps in a vulnerable population of children in rural Pakistan.

Global routine vaccination coverage, 2014.

The year 2014 marked the 40th anniversary of the World Health Organization’s (WHO) Expanded Program on Immunization, which was established to ensure equitable access to routine immunization services (1). Since 1974, global coverage with the four core vaccines (Bacille Calmette- Guérin vaccine [BCG; for protection against tuberculosis], diphtheria-tetanus-pertussis [DTP] vaccine, poliovirus vaccine, and measles vaccine) has increased from <5% to ≥85%, and additional vaccines have been added to the recommended schedule. Coverage with the 3rd dose of DTP vaccine (DTP3) by age 12 months is an indicator of immunization program performance because it reflects completion of the basic infant immunization schedule; coverage with other vaccines, including the 3rd dose of poliovirus vaccine (polio3); the 1st dose of measles-containing vaccine (MCV1) is also assessed. Estimated global DTP3 coverage has remained at 84%–86% since 2009, with estimated 2014 coverage at 86%. Estimated global coverage for the 2nd routine dose of measles-containing vaccine (MCV2) was 38% by age 24 months and 56% when older age groups were included, similar to levels reported in 2013 (36% and 55%, respectively). To reach and sustain high immunization coverage in all countries, adequate vaccine stock management and additional opportunities for immunization, such as through routine visits in the second year of life, are integral components to strengthening immunization programs and reducing morbidity and mortality from vaccine preventable diseases.

National, State, and Selected Local Area Vaccination Coverage Among Children Aged 19-35 Months - United States, 2014.

The reduction in morbidity and mortality associated with vaccine-preventable diseases in the United States has been described as one of the 10 greatest public health achievements of the first decade of the 21st century. A recent analysis concluded that routine childhood vaccination will prevent 322 million cases of disease and about 732,000 early deaths among children born during 1994-2013, for a net societal cost savings of $1.38 trillion. The National Immunization Survey (NIS) has monitored vaccination coverage among U.S. children aged 19-35 months since 1994. This report presents national, regional, state, and selected local area vaccination coverage estimates for children born from January 2011 through May 2013, based on data from the 2014 NIS. For most vaccinations, there was no significant change in coverage between 2013 and 2014. The exception was hepatitis A vaccine (HepA), for which increases were observed in coverage with both ≥1 and ≥2 doses. As in previous years, <1% of children received no vaccinations. National coverage estimates indicate that the Healthy People 2020 target* of 90% was met for ≥3 doses of poliovirus vaccine (93.3%), ≥1 dose of measles, mumps, and rubella vaccine (MMR) (91.5%), ≥3 doses of hepatitis B vaccine (HepB) (91.6%), and ≥1 dose of varicella vaccine (91.0%). Coverage was below target for ≥4 doses of diphtheria, tetanus, and acellular pertussis vaccine (DTaP), the full series of Haemophilus influenzae type b (Hib) vaccine, hepatitis B (HepB) birth dose,† ≥4 doses pneumococcal conjugate vaccine (PCV), ≥2 doses of HepA, the full series of rotavirus vaccine, and the combined vaccine series.§ Examination of coverage by child's race/ethnicity revealed lower estimated coverage among non-Hispanic black children compared with non-Hispanic white children for several vaccinations, including DTaP, the full series of Hib, PCV, rotavirus vaccine, and the combined series. Children from households classified as below the federal poverty level had lower estimated coverage for almost all of the vaccinations assessed, compared with children living at or above the poverty level. Significant variation in coverage by state¶ was observed for several vaccinations, including HepB birth dose, HepA, and rotavirus. High vaccination coverage must be maintained across geographic and sociodemographic groups if progress in reducing the impact of vaccine-preventable diseases is to be sustained.

Effect of a single inactivated poliovirus vaccine dose on intestinal immunity against poliovirus in children previously given oral vaccine: an open-label, randomised controlled trial

Intestinal immunity induced by oral poliovirus vaccine (OPV) is imperfect and wanes with time, permitting transmission of infection by immunised children. Inactivated poliovirus vaccine (IPV) does not induce an intestinal mucosal immune response, but could boost protection in children who are mucosally primed through previous exposure to OPV. We aimed to assess the effect of IPV on intestinal immunity in children previously vaccinated with OPV. We did an open-label, randomised controlled trial in children aged 1-4 years from Chinnallapuram, Vellore, India, who were healthy, had not received IPV before, and had had their last dose of OPV at least 6 months before enrolment. Children were randomly assigned (1:1) to receive 0·5 mL IPV intramuscularly (containing 40, 8, and 32 D antigen units for serotypes 1, 2, and 3) or no vaccine. The randomisation sequence was computer generated with a blocked randomisation procedure with block sizes of ten by an independent statistician. The laboratory staff did blinded assessments. The primary outcome was the proportion of children shedding poliovirus 7 days after a challenge dose of serotype 1 and 3 bivalent OPV (bOPV). A second dose of bOPV was given to children in the no vaccine group to assess intestinal immunity resulting from the first dose. A per-protocol analysis was planned for all children who provided a stool sample at 7 days after bOPV challenge. This trial is registered with Clinical Trials Registry of India, number CTRI/2012/09/003005. Between Aug 19, 2013, and Sept 13, 2013, 450 children were enrolled and randomly assigned into study groups. 225 children received IPV and 225 no vaccine. 222 children in the no vaccine group and 224 children in the IPV group had stool samples available for primary analysis 7 days after bOPV challenge. In the IPV group, 27 (12%) children shed serotype 1 poliovirus and 17 (8%) shed serotype 3 poliovirus compared with 43 (19%) and 57 (26%) in the no vaccine group (risk ratio 0·62, 95% CI 0·40-0·97, p=0·0375; 0·30, 0·18-0·49, p<0·0001). No adverse events were related to the study interventions. The substantial boost in intestinal immunity conferred by a supplementary dose of IPV given to children younger than 5 years who had previously received OPV shows a potential role for this vaccine in immunisation activities to accelerate eradication and prevent outbreaks of poliomyelitis. Bill & Melinda Gates Foundation.

Evolution of Type 2 Vaccine Derived Poliovirus Lineages. Evidence for Codon-Specific Positive Selection at Three Distinct Locations on Capsid Wall

Partial sequences of 110 type 2 poliovirus strains isolated from sewage in Slovakia in 2003–2005, and most probably originating from a single dose of oral poliovirus vaccine, were subjected to a detailed genetic analysis. Evolutionary patterns of these vaccine derived poliovirus strains (SVK-aVDPV2) were compared to those of type 1 and type 3 wild poliovirus (WPV) lineages considered to have a single seed strain origin, respectively. The 102 unique SVK-aVDPV VP1 sequences were monophyletic differing from that of the most likely parental poliovirus type 2/Sabin (PV2 Sabin) by 12.5–15.6%. Judging from this difference and from the rate of accumulation of synonymous transversions during the 22 month observation period, the relevant oral poliovirus vaccine dose had been administered to an unknown recipient more than 12 years earlier. The patterns of nucleotide substitution during the observation period differed from those found in the studied lineages of WPV1 or 3, including a lower transition/transversion (Ts/Tv) bias and strikingly lower Ts/Tv rate ratios at the 2nd codon position for both purines and pyrimidines. A relatively low preference of transitions at the 2nd codon position was also found in the large set of VP1 sequences of Nigerian circulating (c)VDPV2, as well as in the smaller sets from the Hispaniola cVDPV1 and Egypt cVDPV2 outbreaks, and among aVDPV1and aVDPV2 strains recently isolated from sewage in Finland. Codon-wise analysis of synonymous versus non-synonymous substitution rates in the VP1 sequences suggested that in five codons, those coding for amino acids at sites 24, 144, 147, 221 and 222, there may have been positive selection during the observation period. We conclude that pattern of poliovirus VP1 evolution in prolonged infection may differ from that found in WPV epidemics. Further studies on sufficiently large independent datasets are needed to confirm this suggestion and to reveal its potential significance.

Immunogenicity of supplemental doses of poliovirus vaccine for children aged 6–9 months in Moradabad, India: a community-based, randomised controlled trial

The continued presence of polio in northern India poses challenges to the interruption of wild poliovirus transmission and the management of poliovirus risks in the post-eradication era. We aimed to assess the current immunity profile after routine doses of trivalent oral poliovirus vaccine (OPV) and numerous supplemental doses of type-1 monovalent OPV (mOPV1), and compared the effect of five vaccine formulations and dosages on residual immunity gaps. We did a community-based, randomised controlled trial of healthy infants aged 6-9 months at ten sites in Moradabad, India. Serum neutralising antibody was measured before infants were randomly assigned to a study group and given standard-potency or higher-potency mOPV1, intradermal fractional-dose inactivated poliovirus vaccine (IPV, GlaxoSmithKline), or intramuscular full-dose IPV from two different manufacturers (GlaxoSmithKline or Panacea). Follow-up sera were taken at days 7 and 28. Our primary endpoint was an increase of more than four times in antibody titres. We did analyses by per-protocol in children with a blood sample available before, and 28 days after, receiving study vaccine (or who completed study procedures). This trial is registered with Current Controlled Trials, number ISRCTN90744784. Of 1002 children enrolled, 869 (87%) completed study procedures (ie, blood sample available at day 0 and day 28). At baseline, 862 (99%), 625 (72%), and 418 (48%) had detectable antibodies to poliovirus types 1, 2, and 3, respectively. In children who were type-1 seropositive, an increase of more than four times in antibody titre was detected 28 days after they were given standard-potency mOPV1 (5/13 [38%]), higher-potency mOPV1 (6/21 [29%]), intradermal IPV (9/16 [56%]), GlaxoSmithKline intramuscular IPV (19/22 [86%]), and Panacea intramuscular IPV (11/13 [85%]). In those who were type-2 seronegative, 42 (100%) of 42 seroconverted after GlaxoSmithKline intramuscular IPV, and 24 (59%) of 41 after intradermal IPV (p<0·0001). 87 (90%) of 97 infants who were type-3 seronegative seroconverted after intramuscular IPV, and 21 (36%) of 49 after intradermal IPV (p<0·0001). Supplemental mOPV1 resulted in almost total seroprevalence against poliovirus type 1, which is consistent with recent absence of poliomyelitis cases; whereas seroprevalence against types 2 and 3 was expected for routine vaccination histories. The immunogenicity of IPV produced in India (Panacea) was similar to that of an internationally manufactured IPV (GSK). Intradermal IPV was less immunogenic.

Inactivated polio vaccine and global polio eradication

2012 will mark the 24th year of WHO's Global Poliomyelitis Eradication Initiative. 1 WHOGlobal eradication of poliomyelitis by the year 2000. Week Epidemiol Rec. 1988; 63: 161-162 Google Scholar Eradication has proven more difficult than originally envisioned because of geopolitical events, such as war, social disruption, and political indifference; social and cultural issues, such as distrust of poliovirus vaccines and vaccinators; and the unanticipated emergence of virulent vaccine-derived polioviruses in many locations. Few of these obstacles have bewildered the scientific community as much as the low efficacy of the major weapon in the arsenal, trivalent oral polio vaccine (OPV) in regions with dense populations, high birthrates, and poor sanitation resulting from diarrhoea due to enteric pathogens, particularly rotaviruses, and perhaps nutritional deficiencies and other factors. 2 Patriarca PA Wright PF John TJ Factors affecting the immunogenicity of oral poliovirus vaccine in developing countries. Rev Infect Dis. 1991; 13: 926-939 Crossref PubMed Scopus (358) Google Scholar , 3 Myaux JA Unicomb L Besser RE et al. Effect of diarrhea on the humoral response to oral polio vaccination. Pediatr Infect Dis J. 1996; 15: 204-209 Crossref PubMed Scopus (38) Google Scholar This dilemma has been most frustrating in northern India where, in some crowded, resource-poor areas, the overall effectiveness of each trivalent OPV dose is estimated to be 10% and some children have developed paralytic polio after as many as ten doses. 4 Grassly NC Fraser C Wenger J et al. New strategies for the elimination of polio from India. Science. 2006; 314: 1150-1153 Crossref PubMed Scopus (216) Google Scholar Immunogenicity of supplemental doses of poliovirus vaccine for children aged 6–9 months in Moradabad, India: a community-based, randomised controlled trialSupplemental mOPV1 resulted in almost total seroprevalence against poliovirus type 1, which is consistent with recent absence of poliomyelitis cases; whereas seroprevalence against types 2 and 3 was expected for routine vaccination histories. The immunogenicity of IPV produced in India (Panacea) was similar to that of an internationally manufactured IPV (GSK). Intradermal IPV was less immunogenic. Full-Text PDF

Trends in early childhood vaccination coverage: Progress towards US Healthy People 2010 goals

ObjectivesTo evaluate trends in national vaccination coverage from 2000 to 2007 among children aged 19–35 months for at least four doses of diphtheria–tetanus–pertussis vaccine (4+DTaP), three doses of poliovirus vaccine (3+Polio), one dose of measles–mumps–rubella vaccine (1+MMR), three doses of Haemophilus influenzae type b vaccine (3+Hib), three doses of hepatitis B vaccine (3+HepB), one dose of Varicella vaccine (1+Var), and the standard vaccine series of these six vaccines (4:3:1:3:3:1). To predict vaccination coverage levels in 2008–2010 for those vaccines that have not yet reached the Healthy People 2010 coverage targets of 90% for individual vaccines and 80% for the vaccine series. MethodsData were analyzed for 167,086 children aged 19–35 months in the 2000–2007 National Immunization Survey. Vaccination coverage trends were analyzed with weighted least squares linear regression models. Nonlinear Weibull and logarithmic regression models were fitted to these past results, and extrapolation was used to predict vaccination coverage levels for 4+DTaP, 1+Var, and the 4:3:1:3:3:1 series from 2008 to 2010. ResultsFrom 2000 to 2007, observed vaccination coverage increased significantly for four of the six vaccines and the standard vaccine series, and reached the 90% target for 3+Polio, 1+MMR, 3+Hib, and 3+HepB. Increases in coverage were not significant for 1+MMR and 3+Hib; however, coverage for these vaccines was consistently>90% throughout the study period. Both Weibull and logarithmic regression models predicted that coverage with 1+Var and the 4:3:1:3:3:1 series will surpass the 2010 target by 2008, while coverage with 4+DTaP will fall short of the target at 86% in 2010. ConclusionsThe United States is well on the way toward reaching most of the Healthy People 2010 objectives for early childhood vaccination coverage. Enhanced efforts are needed to ensure that these trends continue, and to increase coverage with 4+DTaP.