Anaphylaxis to SARS-CoV-2 Vaccines in the Setting of a Nationwide Passive Epidemiological Surveillance Program.

BACKGROUND: Information on anaphylaxis among recipients of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains scarce. OBJECTIVE: To identify the observed incidence of anaphylaxis in recipients of different anti-SARS-CoV-2 vaccines. METHODS: A nationwide observational study among recipients of 61,414,803 doses of seven different anti-SARS-CoV-2 vaccines, describing the incidence and characteristics of adult patients (age ≥ 18 years) who developed anaphylaxis as an adverse event following immunization (AEFI) against SARS-CoV-2 vaccines between December 24, 2020, and October 15, 2021, in Mexico. RESULTS: Sixty-six patients developed anaphylaxis as an AEFI, for an overall observed incidence of 1.07 cases per 1,000,000 (95% CI 0.84-1.37) administered doses. Eighty-six percent of the patients were female, consistent with previous reports of AEFI to COVID-19 vaccines. mRNA-based vaccine recipients had the highest frequency of anaphylaxis, followed by adenovirus-vectored vaccines and inactivated virus recipients, with an observed incidence of 2.5, 0.7, and 0.2 cases per 1,000,000 doses administered, respectively. Only 46% of the patients received correct treatment with epinephrine as the first-line treatment through the appropriate route and dose. We detected one case of anaphylactic reaction-related death occurring 5 min following immunization with ChAdOx1 nCov-19 for a mortality rate of 1.5% among those who developed this AEFI. CONCLUSIONS: In our population, anaphylactic reactions were infrequent. Our study provides further evidence supporting the security of these newly developed vaccines.

Seizures following COVID-19 vaccination in Mexico: A nationwide observational study.

The COVID-19 pandemic led to the development and emergency approval of an array of effective vaccines against SARS-CoV-2. Given the relatively small number of patients included in vaccine trials, postapproval epidemiological surveillance is crucial to detect infrequent vaccine-related adverse events. We conducted a nationwide retrospective descriptive study evaluating the incidence of seizures among recipients of SARS-CoV-2 vaccines in Mexico from December 24, 2020 (date of administration of first doses nationwide) to October 29, 2021. Among 81 916 351 doses of any vaccine that were administered, we documented seizures in 53 patients, of which 31 (60%) were new onset seizures. The incidence rate of seizures per million doses was highest for mRNA-1273 (Moderna) with 2.73 per million, followed by BNT162b2 (Pfizer-BioNTech) with 1.02 per million, and Ad5-nCoV (CanSino) with 1.01 per million. Thus, we found that seizures following SARS-CoV-2 vaccination are exceedingly rare events.

Incidence of Guillain-Barré syndrome following SARS-CoV-2 immunization: Analysis of a nationwide registry of recipients of 81 million doses of seven vaccines.

BACKGROUND AND PURPOSE: Information on Guillain-Barré syndrome (GBS) as an adverse event following immunization (AEFI) against SARS-CoV-2 remains scarce. We aimed to report GBS incidence as an AEFI among adult (≥18 years) recipients of 81,842,426 doses of seven anti-SARS-CoV-2 vaccines between December 24, 2020, and October 29, 2021, in Mexico. METHODS: Cases were retrospectively collected through passive epidemiological surveillance. The overall observed incidence was calculated according to the total number of administered doses. Vaccines were analyzed individually and by vector as mRNA-based (mRNA-1273 and BNT162b2), adenovirus-vectored (ChAdOx1 nCov-19, rAd26-rAd5, Ad5-nCoV, and Ad26.COV2-S), and inactivated whole-virion-vectored (CoronaVac) vaccines. RESULTS: We identified 97 patients (52 males [53.6%]; median [interquartile range] age 44 [33-60] years), for an overall observed incidence of 1.19/1,000,000 doses (95% confidence interval [CI] 0.97-1.45), with incidence higher among Ad26.COV2-S (3.86/1,000,000 doses, 95% CI 1.50-9.93) and BNT162b2 recipients (1.92/1,00,000 doses, 95% CI 1.36-2.71). The interval (interquartile range) from vaccination to GBS symptom onset was 10 (3-17) days. Preceding diarrhea was reported in 21 patients (21.6%) and mild COVID-19 in four more (4.1%). Only 18 patients were tested for Campylobacter jejuni (positive in 16 [88.9%]). Electrophysiological examinations were performed in 76 patients (78.4%; axonal in 46 [60.5%] and demyelinating in 25 [32.8%]); variants were similar across the platforms. On admission, 91.8% had a GBS disability score ≥3. Seventy-five patients (77.3%) received intravenous immunoglobulin, received seven plasma exchange (7.2%), and 15 (15.5%) were treated conservatively. Ten patients (10.3%) died, and 79.1% of survivors were unable to walk independently. CONCLUSIONS: Guillain-Barré syndrome was an extremely infrequent AEFI against SARS-CoV-2. The protection provided by these vaccines outweighs the risk of developing GBS.

Neurologic adverse events among 704,003 first-dose recipients of the BNT162b2 mRNA COVID-19 vaccine in Mexico: A nationwide descriptive study.

mRNA vaccines against SARS-CoV-2 are remarkably effective. Limited information exists about the incidence of adverse events following immunization (AEFI) with their use. We conducted a prospective observational study including data from 704,003 first-doses recipients; 6536 AEFI were reported, of whom 65.1% had at least one neurologic AEFI (non-serious 99.6%). Thirty-three serious events were reported; 17 (51.5%) were neurologic (observed frequency, 2.4/100,000 doses). At the time of writing this report, 16/17 cases had been discharged without deaths. Our data suggest that the BNT162b2 mRNA COVID-19 vaccine is safe; its individual and societal benefits outweigh the low percentage of serious neurologic AEFI. This information should help to dissipate hesitancy towards this new vaccine platform.

[Trends in vaccination coverage among children aged 12-23 and 24-35 months in Mexico. Ensanut 2012 and Ensanut 100]. / Tendencias en las coberturas de vacunación en niños de 12 a 23 y 24 a 35 meses en México.

OBJECTIVE: To evaluate and compare vaccination coverage among children aged 12-23 and 24-35 months living in localities with less than 100 000 inhabitants in Encuesta Nacional de Salud y Nutrición (Ensanut) 2012 and Ensanut 100k (2018). MATERIALS AND METHODS: Estimate of coverage with both surveys. RESULTS: Between 2012 and 2018, according to proof and self-report, the coverage of the basic scheme was maintained in children aged 12-23 (51.6 vs. 60.2%) and 24-35 months (51.4 vs. 50.0%). Similarly, only with proof (53.9 vs. 51.3% and 52.8 vs. 44.2%). In children aged 24-35 months, the coverage of the reinforced basic scheme reinforcements with probative document and self-report (30.9 vs. 34.0%) and only with reinforcements (30.2 vs. 27.8%) was maintained. Coverage with second and third doses of hepatitis B in both age groups decreased; additionally, first dose of measlesmumps-rubella vaccine (SRP, in Spanish) and third dose of Pentavalent in children aged 24-35 months. CONCLUSIONS: Coverages were maintained by schemes, despite reductions in hepatitis B, pentavalent and SRP.

OBJETIVO: Comparar coberturas de vacunación en niños de 12-23 y 24-35 meses de edad de localidades menores de 100 000 habitantes en México, entre 2012 (Encuesta Nacional de Salud y Nutrición Ensanut] 2012) y 2018 (Ensanut 100k). MATERIAL Y MÉTODOS: Estimación de coberturas con ambas encuestas. RESULTADOS: Entre 2012 y 2018, se mantuvo la cobertura del Esquema básico, con comprobante y autorreporte, en niños de 12-23 (51.6 vs. 60.2%) y 24-35 meses (51.4 vs. 50.0%), y sólo con comprobante (53.9 vs. 51.3% y 52.8 vs. 44.2%). Se mantuvo la cobertura del Esquema básico más refuerzos en niños de 24-35 meses, comprobante y autorreporte (30.9 vs. 34.0%) y sólo con comprobante (30.2 vs. 27.8%). Disminuyeron las coberturas con segunda y tercera dosis de hepatitis B en niños de 12-23 y 24-35 meses, y con primera dosis de triple viral (SRP) y tercera de pentavalente en niños de 24-35 meses. CONCLUSIONES: Se mantuvieron las coberturas del Esquema básico y Esquema básico más refuerzos aunque disminuyeron las coberturas con hepatitis B, pentavalente y SRP.

Seroprevalence of Poliomyelitis Antibodies Among Children Aged 1 to 4 Years Old and Factors Associated With Poliovirus Susceptibility; Mexican Health and Nutrition Survey, 2012.

Background: An essential component of the "Polio Eradication and Endgame Strategic Plan 2013-2018" is the evaluation of population immunity. Mexico introduced the inactivated polio vaccine (IPV) into its routine immunization schedule in 2007 but continued to give trivalent oral polio vaccine OPV twice a year during National Health Weeks through 2016. Methods: To describe the seroprevalence of poliomyelitis among children one to four years old in Mexico and analyze risk factors for susceptibility. We detected antibodies to poliovirus type 1 by microneutralization test in 966 serum samples randomly selected from the National Health and Nutrition Survey, 2012. We assessed variables associated with susceptibility using multivariable logistic regression. Results: The overall weighted seroprevalence of the general population was 98.39% (95% confidence interval [CI] 96.76-99.21). We found significant differences of prevalence according to age (94.39%, 95% CI 87.56-97.58; 99.02%, 95% CI 95.68-99.79; 99.82%, 95% CI 98.77-99.98; and 100% among children 1, 2, 3, and 4 years old respectively) and number of IPV doses (96.91%, 95% CI 90.55-99.44; 100%; 97.85%, 95% CI 94.46-99.18; and 99.92%, 95% CI 99.45-99.98 for 1 2, 3, and 4 number of doses, respectively). Multivariate analyses showed that susceptibility was associated with younger age, fewer doses of IPV, and certain socioeconomic levels. Conclusions: Overall seroprevalence was high. However, we found susceptible children among younger ages and children with fewer or unknown IPV doses belonging to certain socioeconomic strata. Results are relevant for countries transitioning from OPV to IPV and underline the importance of achieving high coverage with IPV.

Protocol Paper: Oral Poliovirus Vaccine Transmissibility in Communities After Cessation of Routine Oral Poliovirus Vaccine Immunization.

Background: We aimed to elucidate household and community-level shedding and transmission of trivalent oral polio vaccine (tOPV) in communities with inactivated polio vaccine (IPV) routine immunization after tOPV is administered during a national health week (NHW). Methods: We conducted a 3-arm, randomized trial with data collected at baseline through 10 weeks post-NHW in households with at least 1 child <5 years old in 3 semi-rural communities in Orizaba, Mexico. Selected communities were geographically isolated but socio-demographically similar. Each community was assigned an oral polio vaccine (OPV) immunization rate: 10, 30, or 70% of participating households. From 2653 households in the 3 communities, ~150 households per community were selected, for 466 in total. Households were randomized as vaccinated or unvaccinated, with only 1 child under 5 in the vaccinated household receiving OPV during the February 2015 NHW. No other community members received OPV during this NHW. Stool samples were collected up to 10 weeks post-vaccination for all members of the 466 study households and were analyzed for the presence of OPV serotypes using a multiplex polymerase chain reaction assay. Results: We will report on the factors associated with, and incidence and duration of, household and community shedding and transmission of OPV. The secondary outcomes will characterize temporal and geospatial OPV serotype shedding patterns. Conclusions: The current global polio eradication plan relies on transitioning away from OPV to IPV. This study contributes to understanding patterns of OPV shedding and transmission dynamics in communities with primary IPV immunity, in order to optimize the reduction of OPV transmission.

Characterization of Household and Community Shedding and Transmission of Oral Polio Vaccine in Mexican Communities With Varying Vaccination Coverage.

Background: The World Health Assembly 2012 Polio Eradication and Endgame Strategic Plan calls for the eventual cessation of all oral polio vaccines (OPVs), to be replaced with inactivated polio vaccine (IPV); however, IPV induces less robust mucosal immunity than OPV. This study characterized household and community OPV shedding and transmission after OPV vaccination within primarily IPV-vaccinated communities. Methods: Households in 3 IPV-vaccinated Mexican communities were randomized to receive 3 levels of OPV vaccination coverage (70%, 30%, or 10%). Ten stool samples were collected from all household members over 71 days. Analysis compared vaccinated subjects, household contacts of vaccinated subjects, and subjects in unvaccinated households. Logistic and Cox regression models were fitted to characterize transmission of OPV by coverage and household vaccination status. Results: Among 148 vaccinated children, 380 household contacts, and 1124 unvaccinated community contacts, 78%, 18%, and 7%, respectively, shed OPV. Community and household contacts showed no differences in transmission (odds ratio [OR], 0.67; 95% confidence interval [CI], .37-1.20), in shedding trajectory (OR, 0.61; 95% CI, .35-1.07), or in time to shedding (hazard ratio, 0.68; 95% CI, .39-1.19). Transmission began as quickly as 1 day after vaccination and persisted as long as 71 days after vaccination. Transmission within unvaccinated households differed significantly across vaccination coverage communities, with the 70% community experiencing the most transmissions (15%), and the 10% community experiencing the least (4%). These trends persisted over time and in the time to first shedding analyses. Conclusions: Transmission did not differ between household contacts of vaccinees and unvaccinated households. Understanding poliovirus transmission dynamics is important for postcertification control.

[[Antibody prevalence to mumps in children and adolescents at two years of the introduction of the MMR vaccine]]. / Prevalencia de anticuerpos frente a parotiditis en niños y adolescentes a dos años de haberse introducido la vacuna SRP.

OBJECTIVE: To assess the prevalence of mumps antibodies in children and adolescents of Mexico, two years after the introduction of the mumps-containing vaccine MMR. MATERIALS AND METHODS: Evaluation of IgG antibodies with a commercial kit of indirect ELISA. RESULTS: 2 111 children (1-9 years) and 2484 adolescents (10-19 years) were studied. The overall antibody seroprevalence was 70.6% (95% CI 69.3-71.9), being higher in adolescents (83.0%, 95%CI 81.5-84.5) than in children (56.0%, 95%CI: 53.9-58.11) (OR 3.83, 95%CI 3.34-4.39, p=0.0000000). Children 1 to 2 and 6 to 9 years who were part of the target group of mumps vaccination since 1998, they had higher seroprevalence than the group of 3 to 5 years unvaccinated. CONCLUSIONS: Seropositivity in children aged 1 to 2 and 6 to 9 years was probably attributable to vaccination during 1998-2000 and in other age groups to natural exposure related to time elapsed in each birth cohort until the study recruitment.

OBJETIVO: Evaluar la prevalencia de anticuerpos antiparotiditis en niños y adolescentes de México, a dos años de haberse introducido la vacuna SRP. MATERIAL Y MÉTODOS: Se estudiaron 2 111 niños (1-9 años) y 2 484 adolescentes (10-19 años). Se evaluaron anticuerpos IgG con un kit comercial de ELISA indirecto. RESULTADOS: La seroprevalencia fue 70.6% (IC95% 69.3-71.9) y resultó mayor en adolescentes (83.0%, IC95% 81.5-84.5) que en niños (56.0%, IC95% 53.9-58.11) (OR 3.83; IC95% 3.34-4.39, p=0.0000000). Los niños de 1 a 2 y de 6 a 9 años, que a partir de 1998 formaron parte del grupo blanco de vacunación vs parotiditis, tuvieron mayor seroprevalencia que el grupo de 3 a 5 años no vacunado. CONCLUSIONES: La seropositividad en niños de 1 a 2 y de 6 a 9 años fue probablemente atribuible a vacunación durante 1998-2000 y la de otros grupos etarios a exposición natural relacionada con el tiempo transcurrido en cada cohorte de nacimientos hasta el reclutamiento al estudio.

[Vaccination coverage and proportion of incomplete vaccination schedule in children under seven years of age in Mexico]. / Cobertura de vacunación y proporción de esquema incompleto en niños menores de siete años en México.

OBJECTIVE: To assess vaccination coverage in children under seven years of age. MATERIALS AND METHODS: Study based on the Halfway National Health and Nutrition Survey (Ensanut MC 2016). RESULTS: Full vaccination coverage in children <1 year was 51.7%, (range: 67.6% [pentavalent (PV)] to 93.9% [BCG]), in those aged 12-23 months was 53.9% (range: 68.5% [MMR] to 98.3% [BCG]) and in those 24-35 months was 63.2% (range: 85.3% [pneumococcal]) to 98.6% [BCG]). In children aged six years, the coverage of 1 MMR dose was 97.8% and 50.7% for two doses. Only 2.2% of six year olds were not vaccinated. Variables associated with incomplete schedule were age of 2-5 months, mother being under 20 years of age or maternal language indigenous. CONCLUSIONS: The vaccination program needs to improve recruitment of newborns and their follow-up until they complete their immunization schedule, taking advantage of the local contacts with health services to vaccinate them.

OBJETIVO: Evaluar la cobertura de vacunación en menores de siete años. MATERIAL Y MÉTODOS: Estudio basado en la Encuesta Nacional de Salud y Nutrición de Medio Camino 2016. RESULTADOS: La cobertura de esquema completo en los niños menores de un año fue de 51.7% [rango: de 67.6%, para la vacuna pentavalente (PV), a 93.9%, para la vacuna Bacillus Calmette-Guerin (BCG)]; en los de 12-23 meses fue de 53.9% [rango: de 68.5%, para la vacuna triple viral (SRP), a 98.3%, para la BCG], y en los de 24-35 meses, de 63.2% [rango: de 85.3%, para la vacuna contra neumococo, a 98.6%, para la BCG]. En niños de seis años, la cobertura de una dosis de SRP fue de 97.8%, y para dos dosis, de 50.7%. Sólo 2.2% de los niños de seis años no estaban vacunados. Las variables asociadas con esquema incompleto fueron edad de 2-5 meses, madre menor de 20 años o hablante de lengua indígena. CONCLUSIONES: Debe mejorarse el reclutamiento de recién nacidos al programa de vacunación, así como su seguimiento, hasta completar el esquema, aprovechando los contactos con los servicios de salud para vacunarlos.

[Analysis of the evidence on the efficacy and safety of CYD-TDV dengue vaccine and its potential licensing and implementation through Mexico's Universal Vaccination Program]. / Análisis de la evidencia sobre eficacia y seguridad de la vacuna de dengue CYD-TDV y su potencial registro e implementación en el Programa de Vacunación Universal de México.

Dengue is a major global public health problem affecting Latin America and Mexico Prevention and control measures, focusing on epidemiological surveillance and vector control, have been partially effective and costly, thus, the development of a vaccine against dengue has created great expectations among health authorities and scientific communities worldwide. The CYD-TDV dengue vaccine produced by Sanofi-Pasteur is the only dengue vaccine evaluated in phase 3 controlled clinical trials. Notwithstanding the significant contribution to the development of a vaccine against dengue, the three phase 3 clinical studies of CYD-TDV and the meta-analysis of the long-term follow up of those studies, have provided evidence that this vaccine exhibited partial vaccine efficacy to protect against virologically confirmed dengue and lead to four considerations: a) adequate vaccine efficacy against dengue virus (DENV) infections 3 and 4, less vaccine efficacy against DENV 1 and no protection against infection by DENV 2; b) decreased vaccine efficacy in dengue seronegative individuals at the beginning of the vaccination; c) 83% and 90% protection against hospitalizations and severe forms of dengue, respectively, at 25 months follow-up; and d) increased hospitalization for dengue in the vaccinated group, in children under nine years of age at the time of vaccination, detected since the third year of follow-up. The benefit of the CYD-TDV vaccine can be summarized in the protection against infection by DENV 3 and 4, as well as protection for hospitalizations and severe cases in people over nine years, who have had previous dengue infection, working mainly as a booster. In this review we identified elements on efficacy and safety of this vaccine that must be taken into account in the licensing process and potential inclusion in the national vaccination program of Mexico. The available scientific evidence on the CYD-TDV vaccine shows merits, but also leads to relevant questions that should be answered to properly assess the safety profile of the product and the target populations of potential benefit. In this regard we consider it would be informative to complete the 6-year follow-up after starting vaccination, according to the company's own study protocol recommended by the World Health Organization. As with any new vaccine, the potential licensing and implementation of the CYD-TDV as part of Mexico's vaccination program, requires a clear definition of the balance between the expected benefits and risks. Particularly with a vaccine with variable efficacy and some signs of risk, in the probable case of licensing, the post-licensed period must involve the development of detailed protocols to immediately identify risks or any health event associated with vaccination.

Lessons learned from the development of a new methodology to assess missed opportunities for vaccination in Latin America and the Caribbean.

The Pan American Health Organization recently developed a practical guide for evaluating missed opportunities for vaccination among children aged <5 years. A missed opportunity occurs when an individual eligible for vaccination has contact with a health facility and does not receive a needed vaccine, despite having no contraindications. In this article, we discuss the strengths and limitations of this new methodology and present lessons learned from recent studies on undervaccination in Latin America. Our findings should be useful to countries embarking on assessing the magnitude and the causes of missed opportunities for vaccination children experience at health facilities.

[Vaccination coverage in children and adolescents in Mexico: vaccinated, under vaccinated and non vaccinated]. / Cobertura de vacunación en niños y adolescentes en México: esquema completo, incompleto y no vacunación.

OBJECTIVE: To assess vaccination coverage of children and adolescents. MATERIALS AND METHODS: Study based on National Health and Nutrition Survey 2012. RESULTS: Coverage in <1 year infants olds infants was <70% for 3 vaccines and <50% for 5. In 15-23 months-olds infants coverage was 59.8% for four vaccines and 51% for six. In 6-year-olds coverage was 93.2% for 1 dose of MMR, and was below 50% for three vaccines in adolescents. Proportion of non-vaccinated individuals was 4.7% in <1-year-olds, 0.2% in 15-23-month-olds, 6.8% in 6-year-olds and 37% in adolescents. Coverage for BCG, HB, and Pneumococcal vaccines in <1-year-olds, and MMR in 15-23-month-olds was >80%. No health insurance and maternal or adolescent illiteracy were explanatory variables for incomplete schema. CONCLUSIONS: Results suggest it is necessary to strengthen information systems, health promotion, training, and daily vaccination without restrictive schedules, ensuring timely and adequate supply of vaccines.

[Vaccination coverage in young, middle age and elderly adults in Mexico]. / Cobertura de vacunación en adultos y adultos mayores en México.

OBJECTIVE: To estimate vaccination coverage in adults 20 years of age and older. MATERIALS AND METHODS: Analysis of data obtained from the National Health and Nutrition Survey 2012. RESULTS: Among adults 20-59 years old coverage with complete scheme, measles and rubella (MR) and tetanus toxoid and diphtheria toxoid (Td) was 44.7,49. and 67.3%, respectively. Coverage and percentage of vaccination were significantly higher among women than men. Among women 20-49 years coverages with complete scheme, MR and Td were 48.3, 53.2 and 69.8%, respectively. Among adults 60-64 years old, coverage with complete scheme, Td and influenza vaccine were 46.5, 66.2 and 56.0%, respectively. Among adults >65 years coverages for complete scheme, Td, influenza vaccine and pneumococcal vaccine were 44.0, 69.0, 63.3 and 62.0%, respectively. CONCLUSION: Vaccination coverage among adult population as obtained from vaccination card or self-report is below optimal values although data may be underestimated. Recommendations for improvements are proposed.

[Acute diarrheal diseases and feeding practices among children under five years in Mexico]. / Diarreas agudas y prácticas de alimentación en niños menores de cinco años en México.

OBJECTIVE: To estimate the prevalence of acute diarrheal diseases (ADD) during the two weeks previous to the interview among children <5 years of age and to describe alarm signs and feeding practices of parents and caregivers (PCG) during children's ADD. MATERIALS AND METHODS: Analysis of data from the National Health and Nutrition Surveys 2012 and 2006 and the National Health Survey 2000. RESULTS: ADD prevalence decreased significantly from 2006 (13.1%) to 2012 (11.0%), particularly in the lower socioeconomic status. "Frequent bowel movements" were the main warning sign identified by PCG (66.0%) in contrast to "crying without tears" (4.3%) and "blood in faeces" (0.5%); only 42% PCG reported administering oral rehydration therapy. Factors associated with ADD were child's age <1 year and mother's age <20 years. CONCLUSIONS: It is necessary to reinforce appropriate ADD preventive and treatment practices among PCG of children <5 years of age.

Aerosolized MMR vaccine: evaluating potential transmission of components to vaccine administrators and contacts of vaccinees.

Although numerous operative and immunological advantages accompany aerosol immunization, potential vaccine virus transmission from the aerosol device to vaccine administrators or from aerosol vaccinees to their contacts requires further study. We conducted a clinical and serological follow-up study of vaccine administrators and matched classroom or household contacts of young adults who received the MMR vaccines by aerosol or injection. Differences in incidence of clinical adverse events between vaccinees and contacts were not statistically significant. No seroresponses to any components of MMR vaccine were noted among 25 matched contacts of persons receiving injected vaccines, and only one equivocal seroresponse was noted among 25 matched contacts of aerosol recipients. No seroresponses were observed in 3 persons who administered aerosol vaccine. The composite findings of this study provide additional evidence of the safety of this approach.

Stroke Among SARS-CoV-2 Vaccine Recipients in Mexico: A Nationwide Descriptive Study.

BACKGROUND AND OBJECTIVES: Information on stroke among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines remains scarce. We report stroke incidence as an adverse event following immunization (AEFI) among recipients of 79,399,446 doses of 6 different SARS-CoV-2 vaccines (BNT162b2, ChAdOx1 nCov-19, Gam-COVID-Vac, CoronaVac, Ad5-nCoV, and Ad26.COV2-S) between December 24, 2020, and August 31, 2021, in Mexico. METHODS: This retrospective descriptive study analyzed stroke incidence per million doses among hospitalized adult patients (≥18 years) during an 8-month interval. According to the World Health Organization, AEFIs were defined as clinical events occurring within 30 days after immunization and categorized as either nonserious or serious, depending on severity, treatment, and hospital admission requirements. Acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), and cerebral venous thrombosis (CVT) cases were collected through a passive epidemiologic surveillance system in which local health providers report potential AEFI to the Mexican General Board of Epidemiology. Data were captured with standardized case report formats by an ad hoc committee appointed by the Mexican Ministry of Health to evaluate potential neurologic AEFI against SARS-COV-2. RESULTS: We included 56 patients (31 female patients [55.5%]) for an overall incidence of 0.71 cases per 1,000,000 administered doses (95% CI 0.54-0.92). Median age was 65 years (interquartile range [IQR] 55-76 years); median time from vaccination to stroke (of any subtype) was 2 days (IQR 1-5 days). In 27 (48.2%) patients, the event was diagnosed within the first 24 hours after immunization. The most frequent subtype was AIS in 43 patients (75%; 0.54 per 1,000,000 doses, 95% CI 0.40-0.73), followed by ICH in 9 (16.1%; 0.11 per 1,000,000 doses, 95% CI 0.06-0.22) and SAH and CVT, each with 2 cases (3.6%; 0.03 per 1,000,000 doses, 95% CI 0.01-0.09). Overall, the most common risk factors were hypertension in 33 (58.9%) patients and diabetes in 22 (39.3%). Median hospital length of stay was 6 days (IQR 4-13 days). At discharge, functional outcome was good (modified Rankin Scale score 0-2) in 41.1% of patients; in-hospital mortality rate was 21.4%. DISCUSSION: Stroke is an exceedingly rare AEFI against SARS-CoV-2. Preexisting stroke risk factors were identified in most patients. Further research is needed to evaluate causal associations between SARS-COV-2 vaccines and stroke.

Psychological and Psychiatric Events Following Immunization with Five Different Vaccines against SARS-CoV-2.

BACKGROUND: Despite the high number of vaccines administered against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide, the information on the psychological/psychiatric adverse events following immunization (AEFI) with these newly developed vaccines remains scarce. OBJECTIVE: To describe the frequency of psychological/psychiatric symptoms among recipients of five different anti-SARS-CoV-2 vaccines and to explore the factors associated with their development reported in the nationwide Mexican registry of AEFI against SARS-CoV-2. METHODS: Descriptive study of all the psychological/psychiatric symptoms, including anxiety, panic attacks, insomnia, and agitation reported to the Mexican Epidemiological Surveillance System from 21 December 2020 to 27 April 2021, among adult (≥18 years old) recipients of 7,812,845 doses of BNT162b2, ChAdOx1 nCov-19, rAd26-rAd5, Ad5-nCoV, or CoronaVac. The factors associated with their development are determined by multivariate regression analysis. RESULTS: There were 19,163 AEFI reports during the study period; amongst them, 191 (1%) patients had psychological/psychiatric symptoms (median age of 41 years, interquartile range of 32-54; 149 [78%] women) for an observed incidence of 2.44 cases per 100,000 administered doses (95% confidence interval [CI] 2.12-2.82), 72.8% of psychiatric AEFIs were reported among recipients of BNT162b2. The median time from vaccination to symptom onset was 35 min (interquartile range: 10-720). Overall, the most common psychological/psychiatric symptoms were anxiety in 129 (67.5%) patients, panic attacks in 30 (15.7%), insomnia in 25 (13%), and agitation in 11 (5.7%). After adjusting for the confounding factors, the odds for developing psychological/psychiatric symptoms were higher for those concurrently reporting syncope (odds ratio [OR]: 4.73, 95% CI: 1.68-13.33); palpitations (OR: 2.47, 95% CI: 1.65-3.70), and dizziness (OR: 1.59, 95% CI: 1.10-2.28). CONCLUSION: In our population, psychological/psychiatric symptoms were extremely infrequent AEFIs. No severe psychiatric AEFIs were reported. Immunization stress-related responses might explain most of the detected cases.

Innovation and immunization program management: traceability and quality in Latin America and the Caribbean, laying the groundwork for a regional action plan.

INTRODUCTION: The Latin American Society of Pediatric Infectious Diseases (SLIPE by its Spanish acronyms) is working to understand the current situation, gaps, and opportunities for traceability of the quality vaccination process in Latin America and the Caribbean. AREAS COVERED: On September 24th and 25th, a Latin American forum of experts in immunization programs was held through the Zoom platform; the topics discussed included: computerized systems for recording immunizations, vaccination programs traceability, challenges, and information systems for the integrated management of vaccination. EXPERT OPINION: Latin American countries have transitioned from having a nominal registration system to a nominal tracking system, with many of them not migrating their platforms to new technologies; therefore, the low-quality data, fragmented databases, and slow information traffic present a challenge that must be taken on.

Transient sensory symptoms among first-dose recipients of the BNT162b2 mRNA COVID-19 vaccine: A case-control study.

mRNA-based COVID-19 vaccines are effective; however, persistent vaccine hesitancy is partly due to a misperception of their potential adverse events. Non-specific sensory symptoms (NSSS) following immunization are thought to be mediated by stress-related responses. In this case-control study, we evaluated NSSS from a cohort of 7,812,845 BNT162b2 first-dose recipients, of whom 10,929 reported an adverse event following immunization (AEFI). We found an overall frequency of 3.4% (377 cases) or 4.8 cases per 100,000 doses administered. Anatomically, the arms (61%) and face/neck region (36.2%) were the most commonly affected sites. The control group had significantly higher rates of reactogenicity-associated symptoms, suggesting that NSSS are reactogenicity-independent; in multivariable analysis, healthcare workers reported sensory symptoms less frequently (aOR 0.54; 95% CI 0.40-0.72;p < 0.001). This is the first study describing the topography and associated factors for developing NSSS among BNT162b2 recipients. The benign nature of these symptoms may help dissipate hesitation towards this vaccine.