Vaccine Effectiveness of CanSino (Adv5-nCoV) Coronavirus Disease 2019 (COVID-19) Vaccine Among Childcare Workers-Mexico, March-December 2021.

BACKGROUND: Beginning in March 2021, Mexico vaccinated childcare workers with a single-dose CanSino Biologics (Adv5-nCoV) coronavirus disease 2019 (COVID-19) vaccine. Although CanSino is currently approved for use in 10 Latin American, Asian, and European countries, little information is available about its vaccine effectiveness (VE). METHODS: We evaluated CanSino VE within a childcare worker cohort that included 1408 childcare facilities. Participants were followed during March-December 2021 and tested through severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reverse-transcription polymerase chain reaction or rapid antigen test if they developed any symptom compatible with COVID-19. Vaccination status was obtained through worker registries. VE was calculated as 100% × (1 - hazard ratio for SARS-CoV-2 infection in fully vaccinated vs unvaccinated participants), using an Andersen-Gill model adjusted for age, sex, state, and local viral circulation. RESULTS: The cohort included 43 925 persons who were mostly (96%) female with a median age of 32 years; 37 646 (86%) were vaccinated with CanSino. During March-December 2021, 2250 (5%) participants had laboratory-confirmed COVID-19, of whom 25 were hospitalized and 6 died. Adjusted VE was 20% (95% confidence interval [CI], 10%-29%) against illness, 76% (95% CI, 42%-90%) against hospitalization, and 94% (95% CI, 66%-99%) against death. VE against illness declined from 48% (95% CI, 33%-61%) after 14-60 days following full vaccination to 20% (95% CI, 9%-31%) after 61-120 days. CONCLUSIONS: CanSino vaccine was effective at preventing COVID-19 illness and highly effective at preventing hospitalization and death. It will be useful to further evaluate duration of protection and assess the value of booster doses to prevent COVID-19 and severe outcomes.

[Lead poisoning and marginalization in newborns of Morelos, Mexico]. / Intoxicación por plomo y nivel de marginación en recién nacidos de Morelos, México.

OBJECTIVE:: To determine the prevalence of lead (Pb) poisoning at birth in Morelos, analyze its distribution by social marginalization level, and estimate the association with the use of lead glazed ceramics (LGC). MATERIALS AND METHODS:: Blood lead level (BLL) in umbilical cord was measured in a representative sample of 300 randomly selected births at the Morelos Health Services and state IMSS. RESULTS:: The prevalence of Pb poisoning at birth (BLL> 5µg/dL) was 14.7% (95%CI: 11.1, 19.3) and 22.2% (95%CI: 14.4, 32.5) in the most socially marginalized municipalities. 57.1% (95%CI: 51.3, 62.7) of the mothers used LGC during pregnancy, and the frequency of use was significantly associated with BLL. CONCLUSION:: This is the first study to document the proportion of newborns with Pb poisoning who are at risk of experiencing the related adverse effects. It is recommended to monitor BLL at birth and take action to reduce this exposure, especially in socially marginalized populations.

Sustained Reduction of Childhood Diarrhea-Related Mortality and Hospitalizations in Mexico After Rotavirus Vaccine Universalization.

BACKGROUND: Mexico implemented routine childhood vaccination against rotavirus in 2007. We describe trends in hospitalization and deaths from diarrhea among children aged <5 years in Mexico before and 7 years after implementation of rotavirus vaccination. METHODS: We obtained data on deaths and hospitalizations from diarrhea, from January 2003 through December 2014, in Mexican children <5 years of age. We compared diarrhea-related mortality and hospitalizations in the postvaccine era with the prevaccine baseline from 2003 to 2006. RESULTS: Compared with the prevaccine baseline, we observed a 53% reduction (95% confidence interval [CI], 47%-58%) in diarrhea-related mortality and a 47% reduction (95% CI, 45%-48%) in diarrhea-related hospitalizations in postvaccine years, translating to 959 deaths and 5831 hospitalizations averted every year in Mexican children aged <5 years. Prevaccine peaks in diarrhea-related mortality and hospitalizations during the rotavirus season months were considerably diminished in postvaccine years, with greater declines observed during the rotavirus season compared with non-rotavirus season months. CONCLUSIONS: We document a substantial and sustained decline in diarrhea-related hospitalizations and deaths in Mexican children associated with implementation of rotavirus vaccination. These results highlight the public health benefits that could result in countries that adopt rotavirus vaccination into their national immunization programs.

Detection of vaccine-derived polioviruses in Mexico using environmental surveillance.

BACKGROUND: Early detection and control of vaccine-derived poliovirus (VDPV) emergences are essential to secure the gains of polio eradication. METHODS: 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). RESULTS: 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 Gutiérrez, 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. CONCLUSIONS: VDPVs may emerge and spread in settings with inadequate coverage with IPV/OPV vaccination. Environmental surveillance can facilitate early detection in these settings.

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

OBJECTIVE: To assess, by socioeconomic setting, the effect of nationwide vaccination against species A rotavirus (RVA) on childhood diarrhoea-related hospitalizations in Mexico. METHODS: 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. FINDINGS: 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. CONCLUSION: Monovalent RVA vaccination has substantially reduced childhood diarrhoea-related hospitalizations for four continuous years in discretely different socioeconomic populations across Mexico.

Contribution of Mexico's Universal Immunization Program to the Fourth Millennium Development Goal.

OBJECTIVE: To identify and describe 1) progress achieved thus far in meeting the commitments of the Fourth Millennium Development Goal (MDG 4) in Mexico, mainly the contribution of the Universal Immunization Program (UIP) over the last 20 years, and 2) new opportunities for further reducing mortality among children under 5 years old. METHODS: An observational, descriptive, retrospective study was carried out to examine registered causes of death in children under 5 between 1990 and 2010. Indicators were built according to the recommendations of the United Nations. RESULTS: In 2010, deaths among children under 5 decreased 64.3% compared to the baseline (1990) figure. Of the total deaths of the children under 5, the neonatal period was the most affected (52.8%), followed by the 1 to 11 months (30.9%), and the 12 to 59 months (16.2%) groups. A 34% overall mortality reduction was observed after the universalization of immunization against influenza, rotavirus, and pneumococcus in children under 5. CONCLUSIONS: Despite a significant reduction in under-5 mortality in Mexico over the last 20 years, largely due to the successes of the UIP, several challenges remain, particularly in improving preventive and curative services during pre- and postnatal care.

Immunogenicity of RV1 and RV5 vaccines administered in standard and interchangeable mixed schedules: a randomized, double-blind, non-inferiority clinical trial in Mexican infants.

Introduction: Rotavirus-associated diarrheal diseases significantly burden healthcare systems, particularly affecting infants under five years. Both Rotarix™ (RV1) and RotaTeq™ (RV5) vaccines have been effective but have distinct application schedules and limited interchangeability data. This study aims to provide evidence on the immunogenicity, reactogenicity, and safety of mixed RV1-RV5 schedules compared to their standard counterparts. Methods: This randomized, double-blind study evaluated the non-inferiority in terms of immunogenicity of mixed rotavirus vaccine schedules compared to standard RV1 and RV5 schedules in a cohort of 1,498 healthy infants aged 6 to 10 weeks. Participants were randomly assigned to one of seven groups receiving various combinations of RV1, and RV5. Standard RV1 and RV5 schedules served as controls of immunogenicity, reactogenicity, and safety analysis. IgA antibody levels were measured from blood samples collected before the first dose and one month after the third dose. Non-inferiority was concluded if the reduction in seroresponse rate in the mixed schemes, compared to the standard highest responding scheme, did not exceed the non-inferiority margin of -0.10. Reactogenicity traits and adverse events were monitored for 30 days after each vaccination and analyzed on the entire cohort. Results: Out of the initial cohort, 1,365 infants completed the study. Immunogenicity analysis included 1,014 infants, considering IgA antibody titers ≥20 U/mL as seropositive. Mixed vaccine schedules demonstrated non-inferiority to standard schedules, with no significant differences in immunogenic response. Safety profiles were comparable across all groups, with no increased incidence of serious adverse events or intussusception. Conclusion: The study confirms that mixed rotavirus vaccine schedules are non-inferior to standard RV1 and RV5 regimens in terms of immunogenicity and safety. This finding supports the flexibility of rotavirus vaccination strategies, particularly in contexts of vaccine shortage or logistic constraints. These results contribute to the global effort to optimize rotavirus vaccination programs for broader and more effective pediatric coverage.Clinical trial registration: ClinicalTrials.gov, NCT02193061.

The rotavirus experience in Mexico: discovery to control.

The recent introduction of a rotavirus vaccine program in Mexico to control rotavirus disease, a common killer of children worldwide, has dramatically reduced the number of Mexican children dying and being hospitalized because of diarrhea. The successful introduction of a rotavirus vaccine program was preceded by several decades of focused research efforts to document the burden of disease and to generate the knowledge base to develop and deploy a vaccine. The postlicensure experience from Mexico demonstrates that evaluating the impact and safety of the vaccination program is vitally necessary for sustaining it. All in all, the immensely successful Mexico experience with control of rotavirus disease, if copied, could yield tremendously favorable results for children and parents worldwide.

Effect of rotavirus vaccination on death from childhood diarrhea in Mexico.

BACKGROUND: A phased introduction of a monovalent rotavirus vaccine occurred in Mexico from February 2006 through May 2007. We assessed the effect of vaccination on deaths from diarrhea in Mexican children in 2008 and 2009. METHODS: We obtained data on deaths from diarrhea, regardless of cause, from January 2003 through May 2009 in Mexican children under 5 years of age. We compared diarrhea-related mortality in 2008 and during the 2008 and 2009 rotavirus seasons with the mortality at baseline (2003-2006), before the introduction of the rotavirus vaccine. Vaccine coverage was estimated from administrative data. RESULTS: By December 2007, an estimated 74% of children who were 11 months of age or younger had received one dose of rotavirus vaccine. In 2008, there were 1118 diarrhea-related deaths among children younger than 5 years of age, a reduction of 675 from the annual median of 1793 deaths during the 2003-2006 period. Diarrhea-related mortality fell from an annual median of 18.1 deaths per 100,000 children at baseline to 11.8 per 100,000 children in 2008 (rate reduction, 35%; 95% confidence interval [CI], 29 to 39; P<0.001). Among infants who were 11 months of age or younger, diarrhea-related mortality fell from 61.5 deaths per 100,000 children at baseline to 36.0 per 100,000 children in 2008 (rate reduction, 41%; 95% CI, 36 to 47; P<0.001). As compared with baseline, diarrhea-related mortality was 29% lower for children between the ages of 12 and 23 months, few of whom were age-eligible for vaccination. Mortality among unvaccinated children between the ages of 24 and 59 months was not significantly reduced. The reduction in the number of diarrhea-related deaths persisted through two full rotavirus seasons (2008 and 2009). CONCLUSIONS: After the introduction of a rotavirus vaccine, a significant decline in diarrhea-related deaths among Mexican children was observed, suggesting a potential benefit from rotavirus vaccination.

A multi-country study of intussusception in children under 2 years of age in Latin America: analysis of prospective surveillance data.

BACKGROUND: Intussusception (IS) is a form of acute intestinal obstruction that occurs mainly in infants and is usually of unknown cause. An association between IS and the first licensed rotavirus vaccine, a reassortant-tetravalent, rhesus-based rotavirus vaccine (RRV-TV), led to the withdrawal of the vaccine. New rotavirus vaccines have now been developed and extensively studied for their potential association with IS. This study aimed to describe the epidemiology and to estimate the incidence of IS in Latin American infants prior to new vaccine introduction. METHODS: Children under 2 years of age representing potential IS cases were enrolled in 16 centers in 11 Latin American countries from January 2003 to May 2005. IS cases were classified as definite, probable, possible or suspected as stated on the Brighton Collaboration Working Group guidelines. RESULTS: From 517 potential cases identified, 476 (92%) cases were classified as definite, 21 probable, 10 possible and 10 suspected for intussusception. Among the 476 definite IS cases, the median age at presentation was 6.4 months with 89% of cases aged <1 year. The male to female ratio was 1.5:1. The incidence of definite IS per 100,000 subject-years ranged from 1.9 in Brazil to 62.4 in Argentina for children <2 years of age, and from 3.8 in Brazil to 105.3 in Argentina for children aged <1 year. Median hospital stay was 4 days with a high prevalence of surgery as the primary treatment (65%). Most cases (88%) made a complete recovery, but 13 (3%) died. No clear seasonal pattern of IS cases emerged. CONCLUSIONS: This study describes the epidemiology and estimates the incidence of IS in Latin American infants prior to the introduction of new rotavirus vaccines. The incidence of IS was found to vary between different countries, as observed in previous studies. TRIAL REGISTRATION: Clinical study identifier 999910/204 (SERO-EPI-IS-204).

Three years of COVID-19 in children that attend the Mexican Social Security Institute's 1,350 child day-care centers, 2020-2023.

Background: Studies have suggested that children are less likely than adults to develop COVID-19; however, with the emergence of SARS-CoV-2 variants, hospitalization and death due to this cause have increased among the youngest ones. Methods: Retrospective, descriptive analytical study of the COVID-19 cases, hospitalizations and deaths occurred in children under five years who attended in Child Day-Care Centers (Centros de Atención Infantil-CAIs) of the Mexican Social Security Institute (IMSS) from 20th July 2020 to 31st March 2023. Results were compared with Mexico's and the US's national-level data. Incidence, attack (children and workers) and mortality rates were estimated. The risks of getting sick, being hospitalized and dying due to COVID-19 were calculated by year. Results: There were 4,369 COVID-19 cases among children from IMSS CAIs; 67 (1.5%) required hospitalization and only two deaths were reported (0.04%). Both at IMSS CAIs and at a national level in Mexico and the US, the highest incidences of COVID-19 among children under five years occurred during Omicron prevalence. The attack rate among workers (32.93%) was higher than children (4.99%). Hospitalization and mortality rates in the US decreased since the anti-COVID 19 vaccine was introduced in children older than six months, unlike the rates in Mexico, where the vaccine for this age group was not available. By the year 2020, the children that attended the IMSS CAIs were 77.3% less likely to be hospitalized; 80.9% in 2021, 93.2% in 2022, and 77.7% by March 2023, compared to same age children in Mexico. In 2021, the children that attended IMSS CAIs were 90.6% less likely to die due to COVID-19, and by March 2023, this likelihood was 34.3% lower than the rest of children in this age group in Mexico. Conclusions: Children that attended IMSS CAIs had a smaller risk of hospitalization and death due to COVID-19. However, the high rates of hospitalization and death due to SARS-CoV-2 in children under five years in our country point to the need and urgency of vaccination against this virus in this age group, as well as of the adherence to strict detection and medical referral protocols.

[Diarrheal disease caused by rotavirus in epidemic outbreaks]. / Enfermedad diarreica por rotavirus en brotes epidémicos.

OBJECTIVE: Determine the epidemiological profile of outbreaks of acute diarrheal disease caused by rotavirus (RV) occurring in pediatric patients, based on a critical review of the literature published between 2000 and 2010. METHODS: A search was carried out for articles published from January 2000 to April 2010, collected by the Artemisa, EBSCO, Embase, Imbiomed, Lilacs, Ovid, PubMed, and Science Direct databases. In the studies that met the inclusion criteria, possible confounding factors were identified and risks of bias were attributed based on the number of items considered inadequate in each case. The epidemiological and microbiological characteristics of the outbreaks were described. RESULTS: The sample was comprised of only 14 (10.8%) of the 129 titles identified, which accounted for 91 092 reported cases of acute diarrhea. In 5 250 of these cases, a search for rotavirus was conducted, yielding 1 711 (32.5%) positive isolations. It was observed that the RV from Group A was the causative agent in 100% of the outbreaks, while genotype G9 was documented in 50% of the articles. CONCLUSIONS: Rotavirus, mainly serotype G9, was one of the principal agents responsible for outbreaks of acute diarrheal disease over the past decade. A careful outbreak study can contribute valuable information for RV disease control and prevention.

Epidemiology of sudden infant death syndrome in Mexico, 2005-2020.

Background: Sudden Infant Death Syndrome (SIDS) constitutes one of the main causes of mortality in children under one year of age in developed countries; it's frequency to varies geographically. In Mexico the real incidence of SIDS is not known. Methods: National databases of deaths in children under one year of age, from 2005 to 2020, were analyzed, due to Sudden Unexpected Infant Death (SUID) [SIDS (R95), accidental suffocation in a sleeping environment (W75), and other ill-defined and unspecified causes of mortality (R99), according to the International Classification of Diseases, tenth revision (ICD 10)]. Mortality rates per year of occurrence due to SUID and their subcategories were calculated. Simple frequencies of SIDS were obtained per year and month of occurrence, state of residence, age, place of death, and access to social security services. Results: In the study period 473,545 infant deaths occurred; 7,714 (1.62%) deaths were due to SUID; of these, 6,489 (84%) were due to SIDS, which is among the 10 leading causes of infant death in Mexico. The average mortality rate for SUID was 22.4/100,000 live births, for SIDS was 18.8/100,000 live births. Mortality rates within the states were variable, ranging from 2.4/100,000 to 105.1/100,000 live births. In 81% of SIDS records there was no autopsy; 38% of deaths due to SIDS occurred in infants under one month of age, up to 87% of deaths occurred in families without social security services or it was unknown, and 76.2% of deaths occurred at home. Deaths were more frequent during the last months of autumn and during winter. Conclusion: In Mexico there is an underregistry of SIDS as cause of death, along with other SUID categories. Health workers need to be trained to improve diagnosis and data registration, including the practice of autopsies; additionally, it is necessary to implement a public health campaign.

Safety and efficacy of an attenuated vaccine against severe rotavirus gastroenteritis.

BACKGROUND: The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial. METHODS: We studied 63,225 healthy infants from 11 Latin American countries and Finland who received two oral doses of either the HRV vaccine (31,673 infants) or placebo (31,552 infants) at approximately two months and four months of age. Severe gastroenteritis episodes were identified by active surveillance. The severity of disease was graded with the use of the 20-point Vesikari scale. Vaccine efficacy was evaluated in a subgroup of 20,169 infants (10,159 vaccinees and 10,010 placebo recipients). RESULTS: The efficacy of the vaccine against severe rotavirus gastroenteritis and against rotavirus-associated hospitalization was 85 percent (P<0.001 for the comparison with placebo) and reached 100 percent against more severe rotavirus gastroenteritis. Hospitalization for diarrhea of any cause was reduced by 42 percent (95 percent confidence interval, 29 to 53 percent; P<0.001). During the 31-day window after each dose, six vaccine recipients and seven placebo recipients had definite intussusception (difference in risk, -0.32 per 10,000 infants; 95 percent confidence interval, -2.91 to 2.18; P=0.78). CONCLUSIONS: Two oral doses of the live attenuated G1P[8] HRV vaccine were highly efficacious in protecting infants against severe rotavirus gastroenteritis, significantly reduced the rate of severe gastroenteritis from any cause, and were not associated with an increased risk of intussusception. (ClinicalTrials.gov numbers, NCT00139347 and NCT00263666.)

Use of Internet Search Data to Monitor Rotavirus Vaccine Impact in the United States, United Kingdom, and Mexico.

BACKGROUND: Previous studies have found a strong correlation between internet search and public health surveillance data. Less is known about how search data respond to public health interventions, such as vaccination, and the consistency of responses in different countries. In this study, we aimed to study the correlation between internet searches for "rotavirus" and rotavirus disease activity in the United States, United Kingdom, and Mexico before and after introduction of rotavirus vaccine. METHODS: We compared time series of internet searches for "rotavirus" from Google Trends with rotavirus laboratory reports from the United States and United Kingdom and with hospitalizations for acute gastroenteritis in the United States and Mexico. Using time and location parameters, Google quantifies an internet query share (IQS) to measure the relative search volume for specific terms. We analyzed the correlation between IQS and laboratory and hospitalization data before and after national vaccine introductions. RESULTS: There was a strong positive correlation between the rotavirus IQS and laboratory reports in the United States (R2 = 0.79) and United Kingdom (R2 = 0.60) and between the rotavirus IQS and acute gastroenteritis hospitalizations in the United States (R2 = 0.87) and Mexico (R2 = 0.69) (P < .0001 for all correlations). The correlations were stronger in the prevaccine period than in the postvaccine period. After vaccine introduction, the mean rotavirus IQS decreased by 40% (95% confidence interval [CI], 25%-55%) in the United States and by 70% (95% CI, 55%-86%) in Mexico. In the United Kingdom, there was a loss of seasonal variation after vaccine introduction. CONCLUSIONS: Rotavirus internet search data trends mirrored national rotavirus laboratory trends in the United States and United Kingdom and gastroenteritis-hospitalization data in the United States and Mexico; lower correlations were found after rotavirus vaccine introduction.

Breastfeeding linked to the reduction of both rotavirus shedding and IgA levels after Rotarix® immunization in Mexican infants.

We examined potential risk factors on vaccine virus shedding and antibody seroresponse to human rotavirus vaccine (Rotarix) in Mexican infants. Two doses of Rotarix were administered to infants during the first two visits for their routine childhood immunization (∼8 and 15weeks of age) in Mexico City. Infant's characteristics and socioeconomic indicators were obtained, including history of long-term feeding practices (exclusively/predominantly breastfed and exclusively/predominantly non-breastfed). Two serum specimens were collected, one during the second rotavirus vaccine visit and one 7weeks later. Stool specimens were collected between days 4-7 after each of the two rotavirus vaccine doses. Rotavirus IgA and IgG titers in serum were determined by enzyme immunoassays (EIA) and rotavirus shedding in stool was assessed by EIA and confirmed by RT-PCR. The overall rotavirus IgA geometric mean titers (GMT) increased significantly post dose 2 from post dose 1 [176 (95%CI: 113-273) to 335 (238-471); p=0.020). Infants who were exclusively/predominantly breastfed were less likely to shed vaccine virus in stool than those who were formula-fed (22% vs. 43%, p=0.016). Infants who were breastfed had lower rotavirus IgA titers than those who were formula-fed after dose 1 [GMT: 145 (84-250) vs. 267 (126-566) p=0.188] and dose 2 [236 (147-378) vs.578 (367-910), p=0.007]. Infants who shed vaccine virus post dose 1 had significantly higher serum IgA GMT than those who did not shed [425 (188-965) vs. 150 (84-266), p=0.038]. Breastfeeding was linked with the reduction of both stool vaccine shedding, and IgA seroresponse. The reduced rotavirus replication in the gut and shedding after dose 1 may explain in part the lower IgA response in serum.

Epidemiological burden of invasive pneumococcal disease in children and adolescents with predisposing risk factors.

OBJECTIVE: Some medical conditions constitute important risk factors for the development of invasive pneumococcal diseases in children and adolescents aged from 5 to 19 years. Conjugate vaccines have potential efficacy in this scenario, but are not available in many Latin American public healthcare systems for this age group. This study aimed to estimate the preventable fraction of invasive pneumococcal diseases among individuals aged from 5 to 19 years with associated risk factors for its development. METHODS: Data regarding the Latin America population, risk factors prevalence and conjugate vaccines efficacy were obtained from the literature. RESULTS: Total population at risk ranged from 17.3 to 64.6 million of individuals and asthma was the most impacting risk factor. According to SIREVA, PCV13 provided a 62.9% serotypes coverage in individuals from 5 to 29 years in 2012, potentially increasing the covered population from [8,338,457-31,057,620] with PCV10 to [10,906,356-40,622,078] with PCV13. To date, according to available efficacy data, the hypothetically immunized population ranged from 11.4 to 42.4 million, representing 7.0% to 26.0% of the total population in this age group. CONCLUSIONS: Vaccination in risk groups should be encouraged, as it potentially contributes to the reduction in the number of cases of invasive pneumococcal disease.

Intention to accept Bordetella pertussis booster vaccine during pregnancy in Mexico City.

OBJECTIVE: Adult booster vaccination against pertussis can help prevent severe infections in young infants. We examined influences on intention to accept pertussis booster vaccination among pregnant women in Mexico City. METHODS: We conducted a cross-sectional survey, recruiting convenience samples of pregnant women receiving prenatal care from three public healthcare centers between March and May 2012. Our primary outcome was intention to accept pertussis vaccination during pregnancy. We examined socio-demographic factors, vaccination history, pertussis knowledge, perceptions of vaccine information sources, and other potential influences on vaccine decision-making. RESULTS: A total of 402 pregnant women agreed to participate, of which 387 (96%) provided their intention to accept or decline pertussis vaccination. Among respondents, 57% intended to accept a pertussis booster vaccine if offered, but only 16% had ever heard of pertussis, and only 2% knew someone who had contracted this disease. Over 80% of respondents would accept pertussis vaccination if recommended by an obstetrician-gynecologist. The most frequently selected reasons to refuse pertussis vaccination were concerns that the vaccine might harm the unborn baby or pregnant woman. In multivariate analysis, rating doctors and nurses as good sources of vaccine information, and having ever heard of pertussis, were independently associated with intention to accept pertussis vaccination. CONCLUSIONS: Promoting patient awareness about pertussis disease and vaccine safety, and encouraging general practitioners, nurses and obstetricians to recommend pertussis booster vaccine, may increase vaccine uptake among pregnant women.

Risk Factors Associated With Rotavirus Gastroenteritis During a Community Outbreak in Chiapas, Mexico During the Postvaccination Era.

BACKGROUND: In January 2010, surveillance detected a rotavirus gastroenteritis outbreak in Chiapas, Mexico. We aimed to identify risk and protective factors for developing rotavirus gastroenteritis of any severity among children in the epidemic setting. METHODS: A case-control study was conducted, comparing case patients (defined as children <36 months of age with acute gastroenteritis of any severity whose stool tested positive for rotavirus by enzyme immunoassay) with age- and municipality-matched controls. Information was obtained through face-to-face interviews on clinical outcome, demographics, breastfeeding history, rotavirus immunization status, and indicators of socioeconomic status. RESULTS: Eighty-five case patients and 170 controls were enrolled. Factors associated with lower risk of rotavirus gastroenteritis included current breastfeeding, owning a refrigerator, and being immunized with 1 or 2 doses of a live-attenuated monovalent rotavirus vaccine. History of previous diarrheal episodes and living with 7 or more people in the same household were associated with higher risk of developing rotavirus gastroenteritis. CONCLUSION: During this outbreak, dietary, socioeconomic, and environmental factors were independently associated with risk of developing rotavirus disease. Rotavirus vaccine also offered significant protection against rotavirus disease of any severity, emphasizing the value of vaccination as a simple and highly effective public health strategy for prevention of rotavirus illness.