关键词： environmental surveillance   inactivated poliovirus vaccine   polio   vaccine-derived poliovirus  

摘要： Background. Early detection and control of vaccine-derived poliovirus (VDPV) emergences are essential to secure the gains of polio eradication. *** integral Serial sewage samples were collected in 4 towns of Mexico before, throughout, and after the May 2010 oral poliovirus vaccine (OPV) mass immunization campaign. Isolation and molecular analysis of polioviruses from sewage specimens monitored the duration of vaccine-related strains in the environment and emergence of vaccine-derived polioviruses in a population partially immunized with inactivated poliovirus vaccine (IPV). *** integral Sabin strains were identified up to 5-8 weeks after the campaign in all towns;in Aguascalientes, 1 Sabin 3 was isolated 16 weeks after the campaign, following 7 weeks with no Sabin strains detected. In Tuxtla Guti,rrez, type 2 VDPV was isolated from 4 samples collected before and during the campaign, and type 1 VDPV from 1 sample collected 19 weeks afterward. During 2009-2010, coverage in 4 OPV campaigns conducted averaged only 57% and surveillance for acute flaccid paralysis (AFP) was suboptimal (AFP rate < 1 per 100 000 population < 15 years of age) in Tuxtla Gutierrez. *** integral VDPVs may emerge and spread in settings with inadequate coverage with IPV/OPV vaccination. Environmental surveillance can facilitate early detection in these settings.

关键词： polio   immunization   poliovirus circulation  

摘要： Background. Inactivated poliovirus vaccine (IPV) is rarely used in tropical developing countries. To generate additional scientific information, especially on the possible emergence of vaccine-derived polioviruses (VDPVs) in an IPV-only environment, we initiated an IPV introduction project in Yogyakarta, an Indonesian province. In this report, we present the coverage, immunity, and VDPV surveillance results. *** integral In Yogyakarta, we established environmental surveillance starting in 2004;and conducted routine immunization coverage and seroprevalence surveys before and after a September 2007 switch from oral poliovirus vaccine (OPV) to IPV, using standard coverage and serosurvey methods. Rates and types of polioviruses found in sewage samples were analyzed, and all poliovirus isolates after the switch were sequenced. *** integral Vaccination coverage (> 95%) and immunity (approximately 100%) did not change substantially before and after the IPV switch. No VDPVs were detected. Before the switch, 58% of environmental samples contained Sabin poliovirus;starting 6 weeks after the switch, Sabin polioviruses were rarely isolated, and if they were, genetic sequencing suggested recent introductions. *** integral This project demonstrated that under almost ideal conditions (good hygiene, maintenance of universally high IPV coverage, and corresponding high immunity against polioviruses), no emergence and circulation of VDPV could be detected in a tropical developing country setting.

关键词： inactivated poliovirus vaccine   IPV   poliomyelitis   immunogenicity   seroconversion   efficacy   eradication   endgame   antibody  

摘要： Background. The World Health Organization has recommended that all 124 countries currently using only oral poliovirus vaccine (OPV) introduce at least 1 dose of inactivated poliovirus vaccine (IPV) before the global withdrawal of serotype 2 OPV in 2016. A 1- or 2-dose schedule, potentially administered intradermally with reduced antigen content, may make this affordable. *** integral A systematic review and meta-analysis of studies documenting seroconversion after 1 or 2, full or fractional (1/5) doses of enhanced-potency IPV was performed. Studies reporting the clinical efficacy of IPV were also reviewed. *** integral Twenty study arms from 12 published articles were included in the analysis of seroconversion. One full dose of intramuscular IPV seroconverted 33%, 41%, and 47% of infants against serotypes 1, 2, and 3 on average, whereas 2 full doses seroconverted 79%, 80%, and 90%, respectively. Seroconversion increased with age at administration. Limited data from case-control studies indicate clinical efficacy equivalent to the proportion seroconverting. One fractional dose of intradermal IPV gave lower seroconversion (10%-40%), but after 2 doses seroconversion was comparable to that with full-dose IPV. *** integral Routine immunization with 2 full or fractional doses of IPV given after 10 weeks of age is likely to protect > 80% of recipients against poliomyelitis if poliovirus reemerges after withdrawal of OPV serotypes.

关键词： 疫苗接种   接种效果   呱呱落地   脊髓灰质炎疫苗   脊灰疫苗   基础免疫   百白破疫苗   乙肝疫苗   联合疫苗   生长发育  

摘要： 为了增强抵抗传染病的能力,预防传染病的发生,需要有计划、按时地给宝宝进行疫苗接种,以保证宝宝的健康成长。可是,几乎每个月都要带宝宝跑医院接种的妈妈们,面对接种表上五花八门的疫苗,犯难了:疫苗,到底该如何选择和接种,才能对宝宝起到最好的保护效果呢?按时、及时为宝宝接种很重要从小baby呱呱落地开始,就面临着被各种病毒和细菌危害的风险,而且在宝宝生长发育的不同阶段各有不同。因此,按时、及时为宝宝接种上正确的疫苗,让宝宝产生足够的保护力就显得尤为重要。例如:

关键词： poliovirus   polio   seroprevalence   OPV   Namibia   adults   pregnant women   population immunity   HIV   neutralizing antibody  

摘要： Background. Poliovirus (PV) antibody seroprevalence studies assess population immunity, verify an immunization program's performance and vaccine efficacy, and guide polio eradication strategy. Namibia experienced a polio outbreak among adults in 2006, yet population seroimmunity was unknown. *** integral We tested 2061 specimens from Namibian pregnant females aged 15-44 years for neutralizing antibody to PV types 1-3 (PV1-3);all females were sampled during the 2010 National HIV Sentinel Survey. We determined the proportion of females seropositive for PV antibody by 5-year age strata, and analyzed factors associated with seropositivity, including age, gravidity, human immunodeficiency virus (HIV) infection status, residence, and antiretroviral treatment, by log-binomial regression. *** integral The seroprevalence was 94.6% for PV1, 97.0% for PV2, and 85.1% for PV3. HIV-positive females had significantly lower seroprevalence than HIV-negative females for PV1 (91.8% vs 95.3%;P < .01) and PV3 (80.0% vs 86.1%;P < .01) but not for PV2 (96.4% vs 97.1%;P = .3). The prevalence ratio of seropositivity for HIV-positive females versus HIV-negative females was 0.95 (95% confidence interval [CI], .92-.98) for PV1, 0.99 (95% CI, .97-1.01) for PV2, and 0.92 (95% CI, .87-.96) for PV3. *** integral Despite relatively high PV seroprevalence, Namibia might remain at risk for a PV outbreak, particularly in lower-seroprevalence populations, such as HIV-positive females. Namibia should continue to maintain high routine polio vaccination coverage.

关键词： poliovirus   Pakistan   molecular epidemiology   environmental surveillance  

摘要： Background. The environmental surveillance has proven to be a useful tool to identify poliovirus circulation in different countries and was started in Pakistan during July 2009 to support the acute flaccid paralysis (AFP) surveillance system. *** integral Sewage samples were collected from 27 environmental sampling (ENV) sites and processed for poliovirus isolation through 2-phase separation method. Poliovirus isolates were identified as Sabin-like or wild type through real-time polymerase chain reaction (PCR). Wild-type strains were subjected to VP1 gene sequencing and phylogenetic analysis performed using MEGA 5.0. *** integral During 2011-2013, a total of 668 samples were collected from 4 provinces that resulted in 40% of samples positive for wild poliovirus type-1 (WPV-1). None of the samples were positive for WPV-3. The areas with high frequency of WPV-1 detection were Karachi-Gadap (69%), Peshawar (82%), and Rawalpindi (65%), whereas the samples from Quetta and Sukkur remained negative for WPV during 2013. Phylogenetic analysis revealed 3 major clusters with multiple poliovirus lineages circulating across different country areas as well as in bordering areas of Afghanistan. *** integral Environmental surveillance in Pakistan has been proven to be a powerful tool to detect WPV circulation in the absence of poliomyelitis cases in many communities. Our findings emphasize the need to continue and expand such surveillance activities to other high-risk areas in the country.

关键词： seroprevalence   wild poliovirus   neutralizing antibodies   OPV formulations   immunogenecity   immunization policies   Moradabad  

摘要： Background. Moradabad district in Uttar Pradesh reported the highest number of paralytic polio cases in India during 2001-2007. We conducted a study in Moradabad in 2007 to assess seroprevalence against poliovirus types 1, 2, and 3 in children 6-12 and 36-59 months of age to guide future strategies to interrupt wild poliovirus transmission in high-risk areas. *** integral Children attending 10 health facilities for minor illnesses who met criteria for study inclusion were eligible for enrollment. We recorded vaccination history, weight, and length and tested sera for neutralizing antibodies to poliovirus types 1, 2, and 3. *** integral Poliovirus type 1, 2, and 3 seroprevalences were 88% (95% confidence interval [CI], 84%-91%), 70% (95% CI, 66%-75%), and 75% (95% CI, 71%-79%), respectively, among 467 in the younger age group (n = 467), compared with 100% (95% CI, 99%-100%), 97% (95% CI, 95%-98%), and 93% (91%-95%), respectively, among 447 children in the older age group (P < .001 for all serotypes). *** integral This seroprevalence study provided extremely useful information that was used by the program in India to guide immunization policies, such as optimizing the use of different OPV formulations in vaccination campaigns and strengthening routine immunization services. Similar surveys in populations at risk should be performed at regular intervals in countries where the risk of persistence or spread of indigenous or imported wild poliovirus is high.

关键词： Namibia   poliomyelitis   type 1 wild poliovirus   disease outbreak   paralysis  

摘要： A paralytic poliomyelitis outbreak occurred in Namibia in 2006, almost exclusively among adults. Nineteen cases were virologically confirmed as due to wild poliovirus type 1 (WPV1), and 26 were classified as polio compatible. Eleven deaths occurred among confirmed and compatible cases (24%). Of the confirmed cases, 97% were aged 15-45 years, 89% were male, and 71% lived in settlement areas in Windhoek. The virus was genetically related to a virus detected in 2005 in Angola, which had been imported earlier from India. The outbreak is likely due to immunity gaps among adults who were inadequately vaccinated during childhood. This outbreak underscores the ongoing risks posed by poliovirus importations, the importance of maintaining strong acute flaccid paralysis surveillance even in adults, and the need to maintain high population immunity to avoid polio outbreaks in the preeradication period and outbreaks due to vaccine-derived polioviruses in the posteradication era.

关键词： assessment   OPV   oral polio vaccine   refusals   noncompliance  

摘要： Background. Accumulation of susceptible children whose caregivers refuse to accept oral poliovirus vaccine (OPV) contributes to the spread of poliovirus in Nigeria. *** integral During and immediately following the OPV campaign in October 2012, polio eradication partners conducted a study among households in which the vaccine was refused, using semistructured questionnaires. The selected study districts had a history of persistent OPV refusals in previous campaigns. *** integral Polio risk perception was low among study participants. The majority (59%) of participants believed that vaccination was either not necessary or would not be helpful, and 30% thought it might be harmful. Religious beliefs were an important driver in the way people understood disease. Fifty-two percent of 48 respondents reported that illnesses were due to God's will and/or destiny and that only God could protect them against illnesses. Only a minority (14%) of respondents indicated that polio was a significant problem in their community. *** integral Caregivers refuse OPV largely because of poor polio risk perception and religious beliefs. Communication strategies should, therefore, aim to increase awareness of polio as a real health threat and educate communities about the safety of the vaccine. In addition, polio eradication partners should collaborate with other agencies and ministries to improve total primary healthcare packages to address identified unmet health and social needs.

关键词： polio eradication   Democratic Republic of Congo   wild poliovirus   importation   molecular epidemiology  

摘要： Background. The last case of polio associated with wild poliovirus (WPV) indigenous to the Democratic Republic of the Congo (DRC) was reported in 2001, marking a major milestone toward polio eradication in Africa. However, during 2006-2011, outbreaks associated with WPV type 1 (WPV1) were widespread in the DRC, with > 250 reported cases. *** integral WPV1 isolates obtained from patients with acute flaccid paralysis (AFP) were compared by nucleotide sequencing of the VP1 capsid region (906 nucleotides). VP1 sequence relationships among isolates from the DRC and other countries were visualized in phylogenetic trees, and isolates representing distinct lineage groups were mapped. *** integral Phylogenetic analysis indicated that WPV1 was imported twice in 2004-2005 and once in approximately 2006 from Uttar Pradesh, India (a major reservoir of endemicity for WPV1 and WPV3 until 2010-2011), into Angola. WPV1 from the first importation spread to the DRC in 2006, sparking a series of outbreaks that continued into 2011. WPV1 from the second importation was widely disseminated in the DRC and spread to the Congo in 2010-2011. VP1 sequence relationships revealed frequent transmission of WPV1 across the borders of Angola, the DRC, and the Congo. Long branches on the phylogenetic tree signaled prolonged gaps in AFP surveillance and a likely underreporting of polio cases. *** integral The reestablishment of widespread and protracted WPV1 transmission in the DRC and Angola following long-range importations highlights the continuing risks of WPV spread until global eradication is achieved, and it further underscores the need for all countries to maintain high levels of poliovirus vaccine coverage and sensitive surveillance to protect their polio-free status.