Influenza Vaccine Recommendations Research Articles

Maternal pertussis and influenza immunization coverage and attitude of health care workers towards these recommendations in Flanders, Belgium

In Belgium, pertussis vaccination is recommended for all pregnant women in every pregnancy. Adults in close contact with young infants are equally advised to receive a pertussis containing booster dose. Maternal influenza vaccination is likewise recommended in Belgium in the second or third trimester of pregnancy, within the influenza season.A quantitative multicenter survey study has been performed between October 2014 and May 2015 in both postpartum women (N=823, response rate=89.2%) and health care workers (HCWs) (N=261) to assess the coverage of both vaccines during pregnancy along with the coverage of the pertussis cocoon strategy, and to evaluate the knowledge and recommending attitude of HCWs towards the maternal vaccination strategies and the cocoon strategy among surveyed women and HCWs.Overall coverage of pertussis vaccination during pregnancy was 64.0%. Most women were vaccinated by their general practitioner (GP) (82.4%), and most often in the third trimester (74.0%) of pregnancy. Overall coverage of influenza vaccination during pregnancy was 45.0%. Again the GP administered most vaccines (67.6%); vaccines were equally administered in the second or third trimester of pregnancy. Educational level had a significant influence on both the pertussis and influenza vaccination coverage during pregnancy while working situation and parity had only an influence on the maternal pertussis vaccination coverage and country of birth only on the maternal influenza vaccination coverage.Overall, 78.4% of gynecologists and GPs recommends both maternal pertussis and influenza vaccination and 67.0% recommends both maternal vaccination strategies and the cocoon strategy. Within the group of the midwives, only 23.7% recommends both maternal pertussis and influenza vaccination and 10.5% recommends both maternal vaccination strategies and the cocoon strategy.High coverage is reached among pregnant women for pertussis and influenza vaccination. Several underserved populations of pregnant women regarding maternal immunization, are identified.

Update From the Advisory Committee on Immunization Practices.

The Advisory Committee on Immunization Practices (ACIP) consists of medical and public health experts who develop recommendations on vaccine use in the United States. The ACIP meets 3 times per year, and members and Centers for Disease Control (CDC) staff present findings and discuss vaccine research, vaccine effectiveness (VE) and safety, clinical trial results, and labeling/package insert information. Outbreaks of vaccine-preventable diseases and vaccine shortages are also discussed. Nonvoting representatives from the American Academy of Pediatrics and the Pediatric Infectious Diseases Society are present. The ACIP met on June 22-23, 2016 to discuss proposed recommendations for influenza vaccination, for human papillomavirus (HPV) vaccine dosing schedules, for the cholera vaccine (CVD 103-HgR), and for the use of MenACWY in human immunodeficiency virus (HIV)-infected persons, as well as an overview of respiratory syncytial virus (RSV) vaccines, safety of maternal tetanus, diphtheria, acellular pertussis (Tdap) immunization, and laboratory containment of poliovirus type 2.

Trends in compliance with two-dose influenza vaccine recommendations in children aged 6 months through 8 years, 2010–2015

BackgroundChildren aged 6 months through 8 years may require two doses of influenza vaccine for adequate immune response against the disease. However, poor two-dose compliance has been reported in the literature. MethodsWe analyzed data for >2.6million children from six immunization information system (IIS) sentinel sites, and assessed full vaccination coverage and two-dose compliance in the 2010–2015 influenza vaccination seasons. Full vaccination was defined as having received at least the recommended number of influenza vaccine doses (one or two), based on recommendations from the Advisory Committee on Immunization Practices. Two-dose compliance was defined as the percentage of children during each season who received at least two doses of influenza vaccine among those who required two doses and initiated the series. ResultsAcross seasons, ⩾1-dose influenza vaccination coverage was mainly unchanged among 6–23montholds (range: 60.9–66.6%), 2–4yearolds (range: 44.8–47.4%), and 5–8yearolds (range: 34.5–38.9%). However, full vaccination coverage showed increasing trends from 2010–11 season to 2014–15 season (6–23months: 43.0–46.5%; 2–4yearolds: 26.3–39.7%; 5–8yearolds, 18.5–33.9%). Across seasons, two-dose compliance remained modest in children 6–23months (range: 63.3–67.6%) and very low in older children (range: 11.6–18.7% in children 2–4yearsand6.8–13.3% in children 5–8years). In the 2014–15 season, among children who required and received 2 doses, only half completed the two-dose series before influenza activity peaked. ConclusionsImproved messaging of the two-dose influenza vaccine recommendations is needed for providers and parents. Providers are encouraged to determine a child’s eligibility for two doses of influenza vaccine using the child’s vaccination history, and to vaccinate children early in the season so that two-dose series are completed before influenza peaks.

The role of healthcare provider attitudes in increasing willingness to accept seasonal influenza vaccine policy changes

BackgroundThis research explored the role of attitudes in acceptance of organizational change initiatives. MethodsA survey assessed factors associated with health care provider (HCP) likelihood to accept seasonal influenza vaccine policy changes. We evaluated the impact of knowledge and individual attitudes on this outcome measure. ResultsKnowledge of seasonal influenza vaccine and influenza recommendations was a significant predictor of HCP’s attitudes toward vaccine at the individual (p<0.001), organizational (p<0.05), and legislative level (p<0.05). Mixed results were obtained when investigating the impact of knowledge on actual willingness to accept vaccine, suggesting that knowledge was only a significant predictor at the organizational (p<0.05) and legislative levels (p<0.05). Attitudes fully mediated the impact of knowledge at both the organizational and legislative levels. InterpretationKnowledge of seasonal influenza and vaccine recommendations is an important, but insufficient predictor of willingness to accept policy change.

Summary of the National Advisory Committee on Immunization (NACI) Statement on Seasonal Influenza Vaccine for 2016-2017.

Influenza is a respiratory infection caused primarily by influenza A and B viruses. Vaccination is the most effective way to prevent influenza and its complications. The National Advisory Committee on Immunization (NACI) provides recommendations regarding seasonal influenza vaccines annually to the Public Health Agency of Canada (the Agency). To summarize the NACI recommendations regarding the use of seasonal influenza vaccines for the 2016-2017 influenza season. Annual influenza vaccine recommendations are developed by NACI's Influenza Working Group for consideration and approval by NACI, based on NACI's evidence-based process for developing recommendations, and include a consideration of the burden of influenza illness and the target populations for vaccination; efficacy and effectiveness, immunogenicity and safety of influenza vaccines; vaccine schedules; and other aspects of influenza immunization. These recommendations are published annually on the Agency's website in the NACI Advisory Committee Statement: Canadian Immunization Guide Chapter on Influenza and Statement on Seasonal Influenza Vaccine (the Statement). The annual NACI seasonal influenza vaccine recommendations have been updated for the 2016-2017 influenza season to include adults with neurologic or neurodevelopment conditions among the groups for whom influenza vaccination is particularly recommended; to include the new high-dose, trivalent inactivated influenza vaccine for use in adults 65 years of age and over; to recommend that egg-allergic individuals may also be vaccinated against influenza using the low ovalbumin-containing live attenuated influenza vaccine (LAIV) licensed for use in Canada (NACI has previously recommended that egg-allergic individuals may be vaccinated using inactivated influenza vaccines); and to remove the preferential recommendation for the use of LAIV in children 2-17 years of age. Two addenda to the 2016-2017 Statement address these new LAIV recommendations. NACI continues to recommend annual influenza vaccination for all individuals aged six months and older, with particular focus on people at high risk of influenza-related complications or hospitalization, people capable of transmitting influenza to those at high risk and others as indicated.

Influenza vaccination: key facts for general practitioners in Europe-a synthesis by European experts based on national guidelines and best practices in the United Kingdom and the Netherlands.

Currently there is no influenza vaccination guidance for European general practitioners. Furthermore, although the European Council recommends a target seasonal influenza vaccination rate of 75% in the elderly (65 years and above) and in anyone aged >6 months with a chronic medical condition, there remain wide discrepancies throughout Europe. A harmonised guideline regarding not only vaccination strategy but also for the consistent diagnosis of influenza across Europe is essential to support a common approach for the implementation of seasonal influenza vaccination across Europe.This document is based on pre-existing guidelines available in the UK and Netherlands and has been approved by a group of European experts for use throughout Europe. As well as providing a standardised influenza diagnosis, it also reviews the current recommendations for influenza vaccination, the types of vaccine available, the contraindications, vaccine use in special populations (in pregnancy, children, and in those with egg allergy), and concomitant administration with other vaccines. The effectiveness, safety, and timing of the seasonal influenza vaccine are also reviewed. A second section provides practical guidance for general practitioners for the implementation of a seasonal influenza vaccination program, including the selection and notification of those eligible for vaccination, as well as suggestions for the organisation of a vaccination programme. Finally, suggested responses to common patient misconceptions and frequently asked questions are included.The aim of this article is to harmonise the diagnosis of seasonal influenza and the approach of European general practitioners to seasonal influenza vaccination in order to better identify influenza outbreaks and to move towards reaching the target vaccination rate of 75% throughout Europe.

Low vaccination coverage for seasonal influenza and pneumococcal disease among adults at-risk and health care workers in Ireland, 2013: The key role of GPs in recommending vaccination

The World Health Organization (WHO), and European Agencies recommend influenza vaccination for individuals at-risk due to age (≥65 years), underlying diseases, pregnancy and for health care workers (HCWs) in Europe. Pneumococcal vaccine is recommended for those at-risk of pneumococcal disease. In Ireland, vaccination uptake among at-risk adults is not routinely available. In 2013, we conducted a national survey among Irish residents ≥18 years of age, to estimate size and vaccination coverage of at-risk groups, and identify predictive factors for influenza vaccination.We used computer assisted telephone interviews to collect self-reported information on health, vaccination status, attitudes towards vaccination. We calculated prevalence and prevalence ratios (PR) using binomial regression.Overall, 1770 individuals participated. For influenza, among those aged 18–64 years, 22% (325/1485) [95%CI: 17%–20%] were at-risk; 28% [95%CI: 23%–33%] were vaccinated. Among those aged ≥65 years, 60% [95%CI: 54%–66%] were vaccinated. Influenza vaccine uptake among HCWs was 28% [95%CI: 21%–35%]. For pneumococcal disease, among those aged 18–64 years, 18% [95%CI: 16%–20%] were at-risk; 16% [95%CI: 12%–21%] reported ever-vaccination; among those aged ≥65 years, 36% [95%CI: 30%–42%] reported ever-vaccination. Main reasons for not receiving influenza vaccine were perceptions of not being at-risk, or not thinking of it; and among HCWs thinking that vaccination was not necessary or they were not at-risk. At-risk individuals were more likely to be vaccinated if their doctor had recommended it (PR 3.2; [95%CI: 2.4%-4.4%]) or they had access to free medical care or free vaccination services (PR 2.0; [95%CI: 1.5%-2.8%]).Vaccination coverage for both influenza and pneumococcal vaccines in at-risk individuals aged 18–64 years was very low. Influenza vaccination coverage among individuals ≥65 years was moderate. Influenza vaccination status was associated with GP vaccination recommendation and free access to vaccination services. Doctors should identify and recommend vaccination to at-risk patients to improve uptake.

Influenza vaccination in high-risk groups: a revision of existing guidelines and rationale for an evidence-based preventive strategy.

Influenza, an infectious respiratory disease, is one of the main causes of excess winter deaths (EWDs) in Europe. Annual flu epidemics are associated with high morbidity and mortality rates, especially among the elderly, those with underlying health conditions and pregnant women. Health Care Workers (HCWs) are also considered at high risk of both contracting influenza and spreading the virus to vulnerable patients. During the 2014/2015 season, the excess winter mortality rates observed in countries of the northern hemisphere (EuroMOMO network) and in Italy (+13%) were strongly related to the intensity of influenza circulation. Influenza vaccination is the most important public health intervention to prevent seasonal influenza transmission and infection. However, to date, influenza vaccination coverage reported in Europe (including high-risk groups) is still largely unsatisfactory. This study analyzes some international and European guidelines on influenza vaccination and the rationale that underlies evidence- based public health intervention for the prevention of influenza among the principal high-risk groups: a) the elderly (subjects aged 65 years or older); b) subjects with underlying health conditions; c) pregnant women; d) healthcare workers. Only by achievement recommended influenza vaccination coverage among high-risk groups in all European countries can we reduce the burden of disease.

Available influenza vaccines: immunization strategies, history and new tools for fighting the disease.

The main public health strategy for containing influenza-related disease is annual vaccination, which is recommended for the elderly and others belonging to risk-factor categories, who present the highest morbidity and mortality, as reported by the World Health Organization (WHO) Recommendations. The availability of different influenza vaccine formulations makes the choice of the best immunization strategy a challenge for stakeholders and public health experts. Heterogeneity in at-risk categories included in national influenza vaccine recommendations still exists, in particular among European countries. Broader consensus is expected, which should positively impact on influenza vaccination coverage. The availability of quadrivalent vaccines, containing both influenza B lineages, offers the potential to improve protection by overcoming the drawbacks of wrongly predicting which B lineage will predominate in a given year.

Annals for Educators - 3 May 2016

<i>Annals</i> for Educators - 3 May 2016

Recommendations and offers for adult influenza vaccination, 2011–2012 season, United States

BackgroundProvider recommendations and offers for influenza vaccination improve adult influenza vaccination coverage. Analysis was performed to describe receipt of influenza vaccination recommendations and offers among adults who visited a healthcare provider (HCP) during the 2011–2012 influenza season and describe differences between those receiving and not receiving recommendations and offers for influenza vaccination. Associations between influenza vaccination and receipt of recommendations and offers were examined. MethodsRespondents to a random digit dial telephone survey who had visited a HCP since July 1, 2011 were asked if they had received a recommendation for influenza vaccination. Those receiving a recommendation were asked if they received an offer for vaccination. Participants were characterized by demographic and access to health care variables. Logistic regression was used to examine the relationships between participant characteristics and recommendation alone, between participant characteristics and recommendation and offer, and between influenza vaccination and recommendation and offer. ResultsOf those who reported visiting a HCP, 43.8% reported receiving a recommendation for influenza vaccination. Of those who reported receiving a recommendation, 76.6% reported receiving an offer for influenza vaccination. Persons with high-risk conditions and persons over 65 years were more likely to receive recommendations for influenza vaccination when compared to those without high-risk conditions and 18–49 year olds, respectively. Those reporting receipt of a recommendation and offer for influenza vaccination were 1.76 times more likely and those reporting receipt of a recommendation but no offer were 1.72 times more likely to report being vaccinated for influenza controlling for all patient characteristics. ConclusionsLess than half of respondents reported receipt of recommendations and offers of influenza vaccination during the 2011–2012 influenza season and disparities exist between groups. All healthcare providers seeing adults should recommend or offer influenza vaccination for all patients at every visit during the influenza season.

Development of Seasonal Influenza Vaccination Recommendations: Relevance and Influence of the Evidence on the Decision-Making Process in France and the Netherlands

BackgroundTarget groups for seasonal influenza vaccination are defined at the country level and are based on several factors. However, little is known about the national decision-making procedures. ObjectiveThe purpose of this study was to compare the evidence used for the development of recommendations and its impact on the choice of target groups in France and the Netherlands. MethodsA preliminary documentary analysis identified institutions to include in the assessment: governmental authorities, research institutions, associations, and manufacturers. At least one expert from each group was invited to our study. Thirty-three semi-structured interviews were conducted in 2013 (16 France, 17 the Netherlands). We used NVivo10® to perform a thematic content analysis. ResultsClinical/epidemiological studies were the evidence most used in both countries. Economic models were increasingly being used; these had greater influence on the decision making in the Netherlands than in France, probably because of the presence of a modeler. Generally, the quality of the evidence used was poor, although no systematic use of standard protocol for its assessment was observed. A general protocol was sometimes used in France; however, the personal judgment of the experts was crucial for the assessment in both countries. ConclusionsThere were differences in the target groups, for example, pregnant women, recommended only in France. France and the Netherlands use similar evidence for developing vaccination recommendations, although different decisions are sometimes made regarding target groups. This could be associated with the lack of systematic standard appraisals, increasing the influence of the experts’ judgment on decision making. The development of standards for the appraisal of evidence is recommended.

Knowledge, attitudes and beliefs related to seasonal influenza vaccine among pregnant women in Thailand

BackgroundIn 2009, Thailand recommended pregnant women be prioritized for influenza vaccination. Vaccine uptake among Thai pregnant women is lower than other high-risk groups. MethodsDuring December 2012–April 2013, we conducted a cross-sectional survey of a convenience sample of Thai pregnant women aged ≥15 years attending antenatal clinics at public hospitals in 8 of 77 provinces. A self-administered questionnaire covered knowledge, attitudes, and beliefs related to influenza vaccination using the Health Belief Model. We examined factors associated with willingness to be vaccinated using log-binomial regression models. ResultsThe survey was completed by 1031 (96%) of 1072 pregnant women approached. A total of 627 (61%) women had heard about influenza vaccine and were included in the analysis, of whom 262 (42%) were willing to be vaccinated, 155 (25%) had received a healthcare provider recommendation for influenza vaccination and 25 (4%) had received the influenza vaccine during the current pregnancy. In unadjusted models, high levels of perceptions of susceptibility (prevalence ratio [PR] 1.5, 95% CI 1.2–2.0), high levels of belief in the benefits of vaccination (PR 2.3, 95% CI 1.7–3.1), moderate (PR 1.7, 95% CI 1.2–2.3) and high (PR 3.4, 95% CI 2.6–4.5) levels of encouragement by others to be vaccinated (i.e., cues to action) were positively associated with willingness to be vaccinated. Moderate (PR 0.5, 95% CI 0.4–0.7) and high levels of (PR 0.5, 95% CI 0.4–0.8) perceived barriers were negatively associated with willingness to be vaccinated. In the final adjusted model, only moderate (PR 1.5, 95% CI 1.1–2.0) and high levels of cues to action (PR 2.7, 95% CI 2.0–3.6) were statistically associated with willingness to be vaccinated. ConclusionCues to action were associated with willingness to be vaccinated and can be used to inform communication strategies during the vaccine campaign to increase influenza vaccination among Thai pregnant women.

Factors associated with a successful expansion of influenza vaccination among pregnant women in Nicaragua

BackgroundPregnant women are at risk of severe influenza disease and are a priority group for influenza vaccination programs. Nicaragua expanded recommendations to include influenza vaccination to all pregnant women in the municipality of Managua in 2013. MethodsWe carried out a survey among 1,807 pregnant women who delivered at public hospitals in the municipality of Managua to evaluate the uptake of influenza vaccination and factors associated with vaccination. ResultsWe observed a high (71%) uptake of influenza vaccination among this population, with no differences observed by age, education or parity of the women. Having four antenatal visits and five or more visits were associated with receipt of influenza vaccination (AORs: 2.58; 95% CI: 1.15, 5.81, and 2.37; 95% CI: 1.12, 5.0, respectively). Also, receipt of influenza vaccination recommendation from a health care provider was positively associated with receipt of influenza vaccination (AOR: 14.22; 95% CI: 10.45, 19.33). ConclusionsThe successful expansion of influenza vaccination among pregnant women in the municipality of Managua may be due to ready access to free medical care and health care providers’ recommendation for vaccination at health care clinics that received influenza vaccine.

Wie werden die Impfempfehlungen gegen saisonale Influenza und gegen humane Papillomaviren in gynäkologischen Praxen umgesetzt?

In Germany, seasonal influenza vaccination has been recommended for pregnant women since 2010 and human papillomavirus (HPV) vaccination for girls since 2007. Gynecologists play an important role in the communication and vaccination of these two target groups. Moreover, seasonal influenza vaccination is also recommended for healthcare workers, as well as adults aged ≥ 60 years and individuals with underlying chronic diseases. The aim of this study was to gain first insights into the acceptance and implementation of the seasonal influenza und HPV vaccination recommendations in gynecological practices. In the context of the national influenza immunization campaign-which is jointly carried out by the Robert Koch Institute (RKI) and the Federal Centre for Health Education (BZgA)-a questionnaire was sent together with influenza information kits to 7477 gynecologists in September 2014. Data from 1469 (20 %) gynecologists were included in the analysis. 72 % of respondents reported that they themselves received a seasonal influenza shot each year. The majority of gynecologists recommended seasonal influenza vaccination for pregnant women (93 %) and HPV vaccination for girls (97 %). The most commonly stated reasons against influenza vaccination were safety concerns. Those against HPV vaccination were effectiveness concerns. Additionally, for both vaccinations the provision of vaccine-related information to the patient was considered too time consuming.The high acceptance of seasonal influenza and HPV vaccination among gynecologists is discordant with the available vaccination coverage figures in Germany. Gynecologists must be reminded of their important role in the prevention of vaccine-preventable diseases in adolescents and adult women. Immunization and communication skills should be considered more strongly as an integral part of medical education and further training for gynecologists.

ADHERENCE TO INFLUENZA VACCINATION AMONG MEDICAL STUDENTS DURING AND AFTER INFLUENZA A (H1N1) PANDEMIC.

SUMMARYThis study evaluated the adherence to influenza vaccination among medical students in 2010 and 2011. From August to December 2011, a questionnaire was used to record the influenza vaccination in 2010 and 2011, reasons for acceptance of the influenza vaccine and knowledge of healthcare workers about the influenza vaccine recommendation. One hundred and forty-four students from the 2ndto the 6th years of the medical school were interviewed. A great adherence to pandemic influenza vaccine was noted in 2010, (91% of the students), with "self-protection" being the most common reason cited for vaccination. Other determinants for the vaccination during pandemic were "convenient access to vaccine" and "encouragement by peers and teachers in workplaces and at the university". However, there was a great decay in the acceptance to vaccine in the next influenza season (2011). Only 42% of the students received the vaccine. They claimed "lack of time" and "have forgotten to take the vaccine" as the main reasons. The "knowledge on the recommendation of influenza vaccine to healthcare workers" increased when the students come to attend the last year of the medical school, but that was an insufficient motivator for vaccination. Strategies to increase vaccination should be based on the abovementioned aspects for the adoption of effective measures in both, pandemic and seasonal periods.

Awareness of Influenza and Attitude Toward Influenza Vaccination Among Medical Students.

In Poland, influenza vaccination coverage among both the general population and healthcare workers is low. The aim of the study was to evaluate attitudes towards influenza vaccination among final-year medical students compared with first-year students at medical schools in Poland. Students were asked about the last season's influenza vaccination and what the reasons were for having, or not having, the vaccination. The knowledge of influenza was assessed using a 10-point visual analog scale. The study group consisted of 712 medical students, 404 in the first year and 308 in the final year (35 % and 31 % of all students in those years, respectively). Final-year students believed they had a better knowledge of influenza (OR = 3.33; CI95%: 2.54-4.39). They answered questions about influenza immunizations (OR = 0.59; CI95%: 0.44-0.78) and vaccination recommendations in pregnant women correctly more frequently (OR = 0.21; CI95%: 0.16-0.28). The influenza vaccination rate among students in the 2014/2015 season was similar (17.1 % in the first vs. 15.9 % in the final year, NS). Among the final-year students, the reason for not having the vaccination was mainly financial and not any other. We conclude that although medical students' knowledge about influenza increases in the course of study, it did not much affect their unwilling attitude toward vaccination.

Perception and Attitudes of Korean Obstetricians about Maternal Influenza Vaccination.

Pregnant women are prioritized to receive influenza vaccination. However, the maternal influenza vaccination rate has been low in Korea. To identify potential barriers for the vaccination of pregnant women against influenza, a survey using a questionnaire on the perceptions and attitudes about maternal influenza vaccination was applied to Korean obstetricians between May and August of 2014. A total of 473 respondents participated in the survey. Most respondents (94.8%, 442/466) recognized that influenza vaccination was required for pregnant women. In addition, 92.8% (410/442) respondents knew that the incidence of adverse events following influenza vaccination is not different between pregnant and non-pregnant women. However, 26.5% (124/468) obstetricians strongly recommended influenza vaccination to pregnant women. The concern about adverse events following influenza vaccination was considered as a major barrier for the promotion of maternal influenza vaccination by healthcare providers. Providing professional information and education about maternal influenza vaccination will enhance the perception of obstetricians about influenza vaccination to pregnant women and will be helpful to improve maternal influenza vaccination coverage in Korea.

A global map of hemispheric influenza vaccine recommendations based on local patterns of viral circulation.

Both the Northern and the Southern Hemisphere annual WHO influenza vaccine recommendations are designed to ensure vaccine delivery before the winter-time peak of viral circulation in each hemisphere. However, influenza seasonal patterns are highly diverse in tropical countries and may be out of phase with the WHO recommendations for their respective hemisphere. We modelled the peak timing of influenza activity for 125 countries using laboratory-based surveillance data from the WHO’s FLUNET database and compared it with the influenza hemispheric recommendations in place. Influenza vaccine recommendations for respectively 25% and 39% of the Northern and Southern Hemisphere countries were out of phase with peak influenza circulation in their corresponding hemisphere (62% and 53%, respectively, when the analysis was limited to the 52 countries in the tropical belt). These results indicate that routine influenza immunization efforts should be closely tailored to local patterns of viral circulation, rather than a country’s hemispheric position.

Continued high incidence of children with severe influenza A(H1N1)pdm09 admitted to paediatric intensive care units in Germany during the first three post-pandemic influenza seasons, 2010/11-2012/13.

BackgroundPrevious influenza surveillance at paediatric intensive care units (PICUs) in Germany indicated increased incidence of PICU admissions for the pandemic influenza subtype A(H1N1)pdm09. We investigated incidence and clinical characteristics of influenza in children admitted to PICUs during the first three post-pandemic influenza seasons, using active screening.MethodsWe conducted a prospective surveillance study in 24 PICUs in Bavaria (Germany) from October 2010 to September 2013. Influenza cases among children between 1 month and 16 years of age admitted to these PICUs with acute respiratory infection were confirmed by PCR analysis of respiratory secretions.ResultsA total of 24/7/20 influenza-associated PICU admissions were recorded in the post-pandemic seasons 1/2/3; incidence estimates per 100,000 children were 1.72/0.76/1.80, respectively. Of all 51 patients, 80 % had influenza A, including 65 % with A(H1N1)pdm09. Influenza A(H1N1)pdm09 was almost absent in season 2 (incidence 0.11), but dominated PICU admissions in seasons 1 (incidence 1.35) and 3 (incidence 1.17). Clinical data was available for 47 influenza patients; median age was 4.8 years (IQR 1.6–11.0). The most frequent diagnoses were influenza-associated pneumonia (62 %), bronchitis/bronchiolitis (32 %), secondary bacterial pneumonia (26 %), and ARDS (21 %). Thirty-six patients (77 %) had underlying medical conditions. Median duration of PICU stay was 3 days (IQR 1–11). Forty-seven per cent of patients received mechanical ventilation, and one patient (2 %) extracorporeal membrane oxygenation; 19 % were treated with oseltamivir. Five children (11 %) had pulmonary sequelae. Five children (11 %) died; all had underlying chronic conditions and were infected with A(H1N1)pdm09. In season 3, patients with A(H1N1)pdm09 were younger than in season 1 (p = 0.020), were diagnosed more often with bronchitis/bronchiolitis (p = 0.004), and were admitted to a PICU later after the onset of influenza symptoms (p = 0.041).ConclusionsActive screening showed a continued high incidence of A(H1N1)pdm09-associated PICU admissions in the post-pandemic seasons 1 and 3, and indicated possible underestimation of incidence in previous German studies. The age shift of severe A(H1N1)pdm09 towards younger children may be explained by increasing immunity in the older paediatric population. The high proportion of patients with underlying chronic conditions indicates the importance of consistent implementation of the current influenza vaccination recommendations for risk groups in Germany.