Age-specific differences in influenza A epidemic curves: do children drive the spread of influenza epidemics?

There is accumulating evidence suggesting that children may drive the spread of influenza epidemics. The objective of this study was to quantify the lead time by age using laboratory-confirmed cases of influenza A for the 1995/1996-2005/2006 seasons from Canadian communities and laboratory-confirmed hospital admissions for the H1N1/2009 pandemic strain. With alignment of the epidemic curves locally before aggregation of cases, slight age-specific differences in the timing of infection became apparent. For seasonal influenza, both the 10-19- and 20-29-year age groups peaked 1 week earlier than other age groups, while during the fall wave of the 2009 pandemic, infections peaked earlier among only the 10-19-year age group. In the H3N2 seasons, infections occurred an average of 3.9 (95% confidence interval: 1.7, 6.1) days earlier in the 20-29-year age group than for youth aged 10-19 years, while during the fall pandemic wave, the 10-19-year age group had a statistically significant lead of 3 days compared with both younger children aged 4-9 years and adults aged 20-29 years (P < 0.0001). This analysis casts doubt on the hypothesis that younger school-age children actually lead influenza epidemic waves.     

Incidence of antiviral drug resistance markers among human influenza A viruses in the Eastern Mediterranean Region, 2005–2016

BackgroundTwo classes of antiviral drugs are available for influenza antiviral therapy: the adamantanes and the neuraminidase inhibitors (NAIs). Due to the emergence of adamantane-resistant variants, the use of these drugs has been largely limited in the world. The NAIs became the drugs of choice for treatment of influenza A infections. However, amino acid substitutions in the NA protein might lead to reduced sensitivity to NAIs.MethodsThe frequency and distribution of matrix protein 2 (M2) and neuraminidase (NA) variants which confer resistance to antiviral drugs was investigated in the Eastern Mediterranean Region (EMR) between 2005 and 2016. A total of 314 M2 and 1209 NA protein sequences from influenza A/H1N1, A/H1N1pdm09, A/H3N2, and A/H5N1 available in the public database were analyzed.ResultsEighty-six percent of the influenza A viruses detected in the EMR were resistant to adamantanes, among which, H3 strains exhibited the highest (95.32%) level of adamantane resistance. Approximately 98.51% (265/269) of influenza A/H1N1 and H3N2 resistant viruses had the S31N substitution in their M2 sequences. The V27A mutation was the only resistance marker found in A/H5N1 viruses and was detected at a frequency of 7.40% among the investigated viruses. Other resistant mutations L26F, A30T, G34E, and L38F were not detected in any of the variants. We found that 2.81% (n = 34) of the detected NA sequences from influenza A viruses possessed at least one NAI-resistant mutation and the vast majority of resistant viruses 79.41% (27/34) bear the H274Y mutation. The frequency of NAI-resistant viruses was 3.29% (24/729) for the H1N1pdm09, 10.64% (5/47) for the seasonal H1N1, and 4.06% (5/123) for H5N1 viruses. None of the H3N2 viruses analyzed during the study period were resistant to NAIs.ConclusionOur study reveals the emergence and spread of antiviral drug resistant influenza A viruses in the EMR and emphasizes the importance of continuous surveillance to maintain the effective use of the current antivirals.     

Significant circulation of influenza B viruses mismatching the recommended vaccine-lineage in South Korea, 2007–2014

We aimed to characterize the lineages of influenza B viruses obtained from clinical specimens during the 2007–2014 seasons in South Korea. RT-PCR for the partial hemagglutinin gene of influenza B virus was performed on laboratory-confirmed influenza B samples from the 2007–2008 season to 2013–2014 season. A phylogenetic tree was generated, and current influenza vaccine strains for the Northern Hemisphere were used as representative strains of Victoria and Yamagata lineages.A total of 571 influenza B virus sequences were analyzed. During the 2009–2010 season, most of the circulating influenza B viruses matched the vaccine strain; 91.0% (91/100) of viruses belonged to the Victoria lineage. In the 2007–2008, 2011–2012, and 2013–2014 seasons, co-circulation of each influenza B lineage was found with a match ratio to the vaccine strain of 53.2% (42/79), 40.9% (63/154), and 58.3% (134/230), respectively. Overall, 41.7% (238/571) of the circulating influenza B viruses belonged to the lineage mismatching the vaccine strain.During the seven influenza seasons, influenza B epidemics were substantial in four seasons in South Korea. Significant mismatches of the vaccine and lineage of the circulating influenza B viruses were found. The current trivalent influenza vaccine may not be fully suitable for effective protection against influenza B.     

Diabetes and changes in functional status of the elderly: a reality?

Diabetes mellitus (DM) is a common disease in the elderly population. The concept of autonomy is linked to a balance between the impairments observed in the daily activities and the availability of resources to compensate these incapacities. In the evolution of the DM, micro and macro vascular complications are commonly observed. The burden of these complications is usually proportional to the duration of the disease and the quality of glycaemic control. Visual alteration and progressive kidney failure requiring haemodialysis have significant impact on the functional status on the elderly diabetic patient living at home. Alterations of cardiac function and peripheral vascular disease which can ultimately lead to lower limb amputation also result in a dramatic alteration in the capacity of elderly patient to carry routine activities of daily living. The presence of DM seems to be a risk factor for cognitive decline and dementia. This article will review the usual complications of DM and link these complications to functional changes in the elderly population.     

Can vaccines control bacterial virulence and pathogenicity? Bordetella pertussis: the advantage of fitness over virulence

Some vaccines, such as diphtheria toxoid and acellular pertussis vaccines (aPVs), may favor the emergence of less pathogenic strains of the respective bacteria they target. This review discusses the impact of the wide use of aPV on Bordetella pertussis phenotype evolutions and their beneficial consequences in the light of the diphtheria toxoid immunization program experience and structuring evidence review in a causal analysis following Bradford Hill’s causality criteria. All aPVs contain the pertussis toxin (PT), the main virulence factor of B.pertussis, alone or with one adhesin (filamentous hemagglutinin (FHA)), two adhesins (FHA and pertactin (PRN)) or four adhesins (FHA, PRN and two fimbriae (Fim 2/3)). In countries where the coverage of aPVs containing PRN is high, PRN negative B.pertussis isolates are increasing in prevalence, but isolates nonproducing the other antigens are rarely reported. We hypothesize that the selective pressure at play with PRN should exist against all aVP antigens, although detection biases may hinder its detection for other antigens, especially PT. PT being responsible for clinically frank cases of the disease, the opportunity to collect PT negative isolates is far lower than to collect PRN negative isolates which have a limited clinical impact. The replacement of the current B.pertussis by far less pathogenic isolates no longer producing the factors contained in aPVs should be expected as a consequence of the wide aPV use.     

Physician unionization in the United States: fad or phenomenon?

This article explores the current trends and issues surrounding physician unionization in the United States, using data from secondary sources and nine interviews with leaders of organizations at the forefront of physician unionizing efforts. Several key points are supported by these data and prior unionization research. First, unions should become a viable organizing alternative for the almost 50% of doctors who are salaried employees because of fewer legal barriers to collective representation, the involvement of national labor unions with resources to spend on organizing, more physicians belonging to demographic groups less hostile to organized labor. and work-related pressures faced by physician-employee under managed care. A second key point is that unions will find it difficult to represent self-employed physicians because of the influence of organized medicine and legal barriers to gaining collective bargaining rights for this group. This discussion is intended to raise awareness of the physician union issue among health care policy-makers and researchers.     

Deficiency and BPC: what changes in the lives of people assisted?

The aim of this article is to analyze the impact of well-being provoked in the life of the disabled people after the Cash Benefit to Disabled People (BPC). The BPC is a social assistance benefit consisting in an unconditional and monthly transference of the equivalent of a minimum wage, to poor people with deficiency and elders with more than 65 years. The methodology used was a case study with qualitative and quantitative techniques of data collection and analysis. BPC performed interviews guided by a semi-structuralized questionnaire with 30 people with deficiency. The results showed that: (1) BPC is an important mechanism of security of income in the consumption of basic goods of feeding, health treatments and expenses with housing of deficient and its families; (2) disabled people had related the concession of the benefit to the increase of social and financial independence in relation to their families, contributing to expand the idea of autonomy and citizenship; (3) it is an instrument capable of protecting the benefited ones and their families of the situation of social vulnerability result of the poverty, although the mothers of the deficient children leave the work market to take care of their children and do not receive any kind of social protection from the State.     

Usage of quadrivalent influenza vaccine among children in the United States, 2013–14

Annual influenza vaccination is recommended for everyone ≥6 months in the U.S. During the 2013–14 influenza season, in addition to trivalent influenza vaccines, quadrivalent vaccines were available, protecting against two influenza A and two influenza B viruses. We analyzed 1,976,443 immunization records from six sentinel sites to compare influenza vaccine usage among children age 6 months–18 years. A total of 983,401 (49.8%) influenza vaccine doses administered were trivalent and 920,333 (46.6%) were quadrivalent (unknown type: 72,709). Quadrivalent vaccine administration varied by age and was least frequent among those <2 years of age.     

Does seasonal vaccination affect the clinical presentation of influenza among the elderly? A cross-sectional analysis in the outpatient setting in France, 2003–2014

Vaccine-induced protection against influenza is not optimal, however it has been suggested that the vaccine may reduce the severity of symptoms among those who develop illness despite being vaccinated. We tested this hypothesis within a countrywide, sentinel general practitioners-based surveillance system in France. We included 2277 individuals aged 65 years or older (of whom 1293 had been vaccinated against influenza, 56.8%) who consulted a general practitioner because of an acute respiratory infection (ARI) during 2003–2014. All patients were taken a nasopharyngeal swab, and information was collected on demographic characteristics and symptoms at disease onset. All specimens were tested for respiratory viruses and, if positive for influenza, the virus type and subtype were determined. We compared the average maximum temperature and the frequency of each symptom, between non-vaccinated and vaccinated influenza patients. We then used logistic regression models to calculate the odds of presenting with each symptom between vaccinated vs. non-vaccinated patients, adjusting by age group, virus (sub)type and season. Overall, 675 ARI patients (29.6%) tested positive for influenza. The A(H3) virus caused the majority of cases (55.1%), followed by influenza B (22.9%), A not-subtyped (11.7%), and A(H1) (10.3%) viruses. Compared to non-vaccinated influenza patients, those who had been vaccinated had a slightly reduced maximum temperature and presented less frequently with myalgia, shivering and headache. In stratified analyses, the observed effect was limited to patients infected with A(H3) or type B viruses. After adjusting by age group, virus (sub)type and season, the difference remained statistically significant only for headache, which was less frequent among vaccinated individuals (odds ratio 0.69, 95% confidence intervals 0.48–0.98). In conclusion, the vaccine was found to be modestly associated with less severe clinical presentation of influenza among the elderly. Our findings reinforce the need for influenza vaccines providing better protection.     

Emergence of new viruses in Asia: is climate change involved?

Tropical Africa is not the only area where deadly viruses have recently emerged. In South-East Asia severe epidemics of dengue hemorrhagic fever started in 1954 and flu pandemics have originated from China such as the Asian flu (H2N2) in 1957, the Hong-Kong flu (H3N2) in 1968, and the Russian flu (H1N1) in 1977. However, it is especially during the last ten years that very dangerous viruses for mankind have repeatedly developed in Asia, with the occurrence of Alkhurma hemorrhagic fever in Saudi Arabia (1995), avian flu (H5N1) in Hong-Kong (1997), Nipah virus encephalitis in Malaysia (1998,) and, above all, the SARS pandemic fever from Southern China (2002). The evolution of these viral diseases was probably not directly affected by climate change. In fact, their emergential success may be better explained by the development of large industry poultry flocks increasing the risks of epizootics, dietary habits, economic and demographic constraints, and negligence in the surveillance and reporting of the first cases.     

Influenza vaccination of staff in aged care facilities in the ACT: how can we improve the uptake of influenza vaccine?

OBJECTIVE: To examine the self-reported uptake of influenza vaccine by staff in residential aged care facilities in the Australian Capital Territory (ACT), and the factors influencing vaccine uptake by staff. METHODS: Two confidential cross-sectional surveys were conducted in all (n = 19) residential aged care facilities in the ACT in June 2000. An interview with directors of each facility collected information on the institutional policy and practices for influenza vaccination. An anonymous postal survey of staff collected information on self-reported influenza vaccination status and staff awareness and attitudes to the vaccination. RESULTS: All directors were interviewed (n = 19) and 50% of staff questionnaires (n = 587) were completed. Of respondents, 28% reported receiving influenza vaccine for the 2000 influenza season. Uptake of the vaccine was associated with particular policies and practices of facilities such as: organisation of vaccination for staff (OR 2.52, CI 1.38-4.59, p < 0.001); provision of reminders to staff (OR 2.73, CI 1.70-4.06, p < 0.001); and provision of information on the need for vaccination (OR 1.94, CI 1.03-3.67, p < 0.001). Other factors significantly associated with influenza vaccine uptake included: previous uptake of the vaccine (OR 52.2, CI 35.2-77.4, p < 0.001), vaccination arranged by the workplace (OR 4.02, CI 2.66-6.07, p < 0.001), and awareness of recommendations for staff employed in aged care facilities (OR 3.66, CI 2.28-5.85, p < 0.001). The main reasons given for not receiving the vaccine were the belief that it had significant side effects (42%, n = 146), and concerns about its effectiveness (32%, n = 109). CONCLUSIONS: This study identified a number of factors that can be incorporated into strategies and programs to improve uptake of influenza vaccine by staff in residential aged care facilities.