Timing of influenza epidemics and vaccines in the American tropics, 2002–2008, 2011–2014

Durand, Lizette O.; Cheng, Po‐Yung; Palekar, Rakhee; Clará, Wilfrido; Jara, Jorge; Cerpa, Mauricio; Omeiri, Nathalie El; Ropero-Álvarez, Alba María; Ramirez, Juliana Barbosa; Araya, Jenny Lara; Acosta, Belsy; Bruno, Alfredo; Lozano, Celina Calderon de; Signor, Leticia del Carmen Castillo; Matute, María Luisa; Jackson‐Betty, Sandra; Mung, Kam; Dí­az-Quiñónez, José Alberto; López-Martı́nez, Irma; Balmaseda, Ángel; Arévalo, Brechla Morneo; Vázquez, Cynthia; Gutierrez, Victoria; Garten, Rebecca; Widdowson, Marc‐Alain; Azziz‐Baumgartner, Eduardo

doi:10.1111/irv.12371

Cited by 44 publications

(49 citation statements)

References 11 publications

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“…Overall, the partition into three large transmission zones that was made by WHO (Central America Caribbean from Mexico in the North to Panama in the South; Tropical South America from Colombia in the North to Peru, Bolivia and Brazil in the South; and Temperate South America including Chile, Argentina, Uruguay and Paraguay) [24] does not seem fully appropriate as it overlooks some of the differences we observed (for example, between regions in Brazil and between neighbouring countries in central America). Data from the literature for countries not included in our database [20, 25–27] provide further support for this view.…”

Section: Discussionmentioning

confidence: 54%

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Characteristics of seasonal influenza A and B in Latin America: Influenza surveillance data from ten countries

Caini

Alonso

Balmaseda³

et al. 2017

PLoS ONE

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IntroductionThe increased availability of influenza surveillance data in recent years justifies an actual and more complete overview of influenza epidemiology in Latin America. We compared the influenza surveillance systems and assessed the epidemiology of influenza A and B, including the spatio-temporal patterns of influenza epidemics, in ten countries and sub-national regions in Latin America.MethodsWe aggregated the data by year and country and characteristics of eighty-two years were analysed. We calculated the median proportion of laboratory-confirmed influenza cases caused by each virus strain, and compared the timing and amplitude of the primary and secondary peaks between countries.Results37,087 influenza cases were reported during 2004–2012. Influenza A and B accounted for a median of 79% and, respectively, 21% of cases in a year. The percentage of influenza A cases that were subtyped was 82.5%; for influenza B, 15.6% of cases were characterized. Influenza A and B were dominant in seventy-five (91%) and seven (9%) years, respectively. In half (51%) of the influenza A years, influenza A(H3N2) was dominant, followed by influenza A(H1N1)pdm2009 (41%) and pre-pandemic A(H1N1) (8%). The primary peak of influenza activity was in June-September in temperate climate countries, with little or no secondary peak. Tropical climate countries had smaller primary peaks taking place in different months and frequently detectable secondary peaks.ConclusionsWe found that good influenza surveillance data exists in Latin America, although improvements can still be made (e.g. a better characterization of influenza B specimens); that influenza B plays a considerable role in the seasonal influenza burden; and that there is substantial heterogeneity of spatio-temporal patterns of influenza epidemics. To improve the effectiveness of influenza control measures in Latin America, tropical climate countries may need to develop innovative prevention strategies specifically tailored to the spatio-temporal patterns of influenza in this region.

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Section: Discussionmentioning

confidence: 54%

“…vaccinating in April using the Southern hemisphere formulation in all countries except Mexico and Cuba) [20]. However, it is critical to note that the proportion of cases preventable with a single dose of influenza vaccine administered in April-May will vary considerably between countries and across years within the same country.…”

Section: Discussionmentioning

confidence: 99%

Characteristics of seasonal influenza A and B in Latin America: Influenza surveillance data from ten countries

Caini

Alonso

Balmaseda³

et al. 2017

PLoS ONE

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“…Central American countries collaborated and pooled their national antigenic characterization data into a regional analysis and confirmed that the Southern Hemisphere formulation corresponded to the most updated formulation available before the start of influenza seasons. The analysis of influenza surveillance data from 2002–2008 and 2011–2014 in the American tropics (101 y of cumulative data; 403,584 specimens tested) indicated that 13 (81%) of 16 participating countries had influenza epidemics that, on average, started during May and lasted 4 months 12 . This regional analysis was a decisive element for the policy adjustments and for developing regional TAG recommendations in July 2015 8 .…”

Section: Resultsmentioning

confidence: 99%

“…Contrarily to countries from temperate zones such as Argentina, Chile and Uruguay, where well-defined influenza seasons have allowed for an optimal planning of vaccination, tropical countries have historically had difficulties characterizing the seasonality of influenza viruses' circulation. Three sub-regions, namely the Southern Cone, the Andean region and Central America show virus circulation that is typical of the Southern Hemisphere (peak activity mid-year) 12,15 . (Supplemental Fig.…”

Section: Introductionmentioning

confidence: 99%

Influenza vaccination in the Americas: Progress and challenges after the 2009 A(H1N1) influenza pandemic

Ropero-Álvarez

Omeiri

Kurtis

et al. 2016

Human Vaccines & Immunotherapeutics

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Background: There has been considerable uptake of seasonal influenza vaccines in the Americas compared to other regions. We describe the current influenza vaccination target groups, recent progress in vaccine uptake and in generating evidence on influenza seasonality and vaccine effectiveness for immunization programs. We also discuss persistent challenges, 5 years after the A(H1N1) 2009 influenza pandemic.Methods: We compiled and summarized data annually reported by countries to the Pan American Health Organization/World Health Organization (PAHO/WHO) through the WHO/UNICEF joint report form on immunization, information obtained through PAHO's Revolving Fund for Vaccine Procurement and communications with managers of national Expanded Programs on Immunization (EPI).Results: Since 2008, 25 countries/territories in the Americas have introduced new target groups for vaccination or expanded the age ranges of existing target groups. As of 2014, 40 (89%) out of 45 countries/territories have policies established for seasonal influenza vaccination. Currently, 29 (64%) countries/territories target pregnant women for vaccination, the highest priority group according to WHO´s Stategic Advisory Group of Experts and PAHO/WHO's Technical Advisory Group on Vaccine-preventable Diseases, compared to only 7 (16%) in 2008. Among 23 countries reporting coverage data, on average, 75% of adults ≥60 years, 45% of children aged 6–23 months, 32% of children aged 5–2 years, 59% of pregnant women, 78% of healthcare workers, and 90% of individuals with chronic conditions were vaccinated during the 2013–14 Northern Hemisphere or 2014 Southern Hemisphere influenza vaccination activities. Difficulties however persist in the estimation of vaccination coverage, especially for pregnant women and persons with chronic conditions. Since 2007, 6 tropical countries have changed their vaccine formulation from the Northern to the Southern Hemisphere formulation and the timing of their campaigns to April-May following the review of national evidence. LAC countries have also established an official network dedicated to evaluating influenza vaccines effectiveness and impact.Conclusion: Following the A(H1N1)2009 influenza pandemic, countries of the Americas have continued their efforts to sustain or increase seasonal influenza vaccine uptake among high risk groups, especially among pregnant women. Countries also continued strengthening influenza surveillance, immunization platforms and information systems, indirectly improving preparedness for future pandemics. Influenza vaccination is particularly challenging compared to other vaccines included in EPI schedules, due to the need for annual, optimally timed vaccination, the wide spectrum of target groups, and the limitations of the available vaccines. Countries should continue to monitor influenza vaccination coverage, generate evidence for vaccination programs and implement social communication strategies addressing existing gaps.

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“…Between June 29 and August 9, 2016--months when influenza typically circulates in Nicaragua [4]--we approached all women who attended prenatal and postpartum visits at the German Nicaraguan Hospital, the Bertha Calderón Roque Hospital and 140 primary healthcare facilities in Managua until sample size was achieved. Women had to have been pregnant during the months of May and June and residents of the Department of Managua in order to participate in the survey.…”

Section: Methodsmentioning

confidence: 99%

Knowledge, attitudes and practices about influenza vaccination among pregnant women and healthcare providers serving pregnant women in Managua, Nicaragua

Arriola

Vasconez²,

Bresee

et al. 2018

Vaccine

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Background Nicaragua implemented an influenza vaccination program for pregnant women with high-risk obstetric conditions in 2007. In 2014, the recommendation of influenza vaccination expanded to include all pregnant women. Given the expansion in the recommendation of vaccination, we evaluated knowledge, attitudes and practices of pregnant women and their healthcare providers towards influenza vaccination and its recommendation. Methods We conducted surveys among pregnant women and their healthcare providers from June to August 2016 at two hospitals and 140 health facilities in Managua. The questions were adapted from the U.S. national CDC influenza survey and related to knowledge, attitudes and practices about influenza vaccination and barriers to vaccination. We analyzed reasons for not receiving vaccination among pregnant women as well as receipt of vaccination recommendation and offer by their healthcare providers. Results Of 1,303 pregnant women enrolled, 42% (5 4 5) reported receiving influenza vaccination in the 2016 season. Of those who reported not receiving vaccination, 46% indicated barriers to vaccination. Pregnant women who were vaccinated were more likely to be aware of the recommendation for vaccination and the risks of influenza illness during pregnancy and to perceive the vaccine as safe and effective, compared to unvaccinated pregnant women (p-values < 0.001). Of the 619 health workers enrolled, over 89% recalled recommending influenza vaccination to all pregnant women, regardless of obstetric risk. Of the 1,223 women who had a prenatal visit between the start date of the influenza vaccination and the time of interview, 44% recalled receiving a recommendation for influenza vaccination and 43% were offered vaccination. Vaccination rates were higher for those receiving a recommendation and offer of vaccination compared with those who received neither (95% vs 5%, p-value < 0.001). Conclusion Pregnant women in Managua had positive perceptions of influenza vaccine and were receptive to receiving influenza vaccination, especially after the offer and recommendation by their healthcare providers.

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Timing of influenza epidemics and vaccines in the American tropics, 2002–2008, 2011–2014

Cited by 44 publications

References 11 publications

Characteristics of seasonal influenza A and B in Latin America: Influenza surveillance data from ten countries

Characteristics of seasonal influenza A and B in Latin America: Influenza surveillance data from ten countries

Influenza vaccination in the Americas: Progress and challenges after the 2009 A(H1N1) influenza pandemic

Knowledge, attitudes and practices about influenza vaccination among pregnant women and healthcare providers serving pregnant women in Managua, Nicaragua

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