Patterns of influenza B circulation in Brazil and its relevance to seasonal vaccine composition

Abstract Data on the burden of disease and circulation patterns of influenza B lineages for Brazil are limited. This review aims to describe the pattern of influenza B occurrence in Brazil to have a better understanding of its epidemiology and its relevance when considering seasonal influenza vaccine composition. A review of the data including analysis of international and local surveillance data as well as information from online search of databases using Medical Subject Headings terms in conjunction with screening of abstracts from scientific events was performed. Based on international epidemiologic surveillance data, moderate levels of influenza B disease (19%; 2006–2014) were observed. Of these nine years, it was possible to compare data from three years (2007, 2008 and 2013) which have information on the circulating influenza B lineage. Co-circulation of influenza B lineages was observed in all these three influenza seasons, of which, during one season, a high degree of mismatch between the vaccine lineage and the predominant circulating lineage (91.4% [2013]) was observed. Local surveillance data reveal a distinct and dynamic distribution of respiratory viruses over the years. Data from published literature and abstracts show that influenza B is a significant cause of disease with an unpredictable circulation pattern and showing trends indicating reemergence of the B/Victoria lineage. The abstracts report notable levels of co-circulation of both influenza B lineages (2000–2013). Mismatch between the Southern hemisphere vaccine and the most prevalent circulating viruses in Brazil were observed in five influenza seasons. The evidence on co-circulation of two influenza B lineages and mismatched seasons in Brazil indicates the benefit of quadrivalent influenza vaccines in conferring broader seasonal influenza protection. Additionally, improving influenza surveillance platforms in Brazil is important for monitoring disease trends and the impact of introducing seasonal influenza vaccination.

Comparison of the direct fluorescence assay and real-time polymerase chain reaction for the detection of influenza virus A and B in immunocompromised patients

OBJECTIVE: This study evaluated the diagnostic performance of two methods for the detection of influenza virus in immunocompromised transplant patients. METHODS: A total of 475 respiratory samples, 236 from patients in a hematopoietic stem cell transplantation program and 239 from kidney transplant patients, were analyzed by a direct fluorescence assay and the Centers for Disease Control real-time polymerase chain reaction protocol for influenza A and B detection. RESULTS: Influenza detection using either method was 7.6% in the hematopoietic stem cell transplant group and 30.5% in the kidney transplant patient group. Influenza detection by real-time polymerase chain reaction yielded a higher positive rate compared with fluorescence than that reported by other studies, and this difference was more pronounced for influenza A. The fluorescence assay sensitivity, specificity, positive and negative predictive values, and kappa coefficient were 17.6%, 100%, 1, 0.83, and 0.256, respectively, and lower detection rates occurred in the kidney transplant patients. CONCLUSIONS: The real-time polymerase chain reaction performance and the associated turnaround time for a large number of samples support the choice of this method for use in different routine diagnostic settings and influenza surveillance in high-risk patients. .

Safety and Immunogenicity of a New Trivalent Inactivated Split-virus Influenza Vaccine in Healthy Korean Children: A Randomized, Double-blinded, Active-controlled, Phase III Study

We report results of a randomized, double-blinded, active-controlled, phase III study conducted to evaluate the immunogenicity and safety of a new trivalent inactivated split-virus influenza vaccine (GC501) manufactured by the Green Cross Corporation in Korea. A total of 283 healthy children aged 6 months to < 18 yr were randomized to receive either GC501 or control. Of the GC501 recipients, seroconversion occurred in 48.5% for A/H1N1, 67.7% for A/H3N2 and 52% for influenza B. The proportion of subjects who had post-vaccination hemagglutination-inhibition titers of 1:40 or greater was 90.7% for A/H1N1, 86.8% for A/H3N2 and 82.4% for influenza B in the GC501 recipients. No serious adverse events related to vaccination, or withdrawals because of adverse events were reported. The majority of solicited adverse events were mild in intensity. GC501 vaccine has good tolerability and favorable immunogenicity in children aged 6 months to < 18 yr. The addition of one more brand of influenza vaccine may allow for better global accessibility of vaccine for epidemics or future pandemics.

Effectiveness of influenza vaccination in prevention of influenza-like illness among inhabitants of old folk homes.

The aims of the study were to determine the attack rate of influenza-like illness among inhabitants of five old folk homes nationwide using influenza vaccine as a probe and the effectiveness of influenza vaccination in prevention of influenza-like illness. We conducted a nonrandomized, single-blind placebo control study from June 2003 to February 2004. VAXIGRIP(R) 2003 Southern hemisphere formulation was used. Among 527 subjects, the attack rates of influenza-like illness in the influenza vaccine group were 6.4, 4.6 and 2.4% during the first, second and third 2-month periods, respectively. The attack rates of influenza-like illness in the placebo group were 17.7, 13.8 and 10.1%. Influenza vaccination reduced the risk of contracting influenza-like illness by between 14, and 45%. The vaccine effectiveness in reducing the occurrence of influenza-like illness ranged from 55 to 76%, during the 6-month study followup. The presence of cerebrovascular diseases significantly increased the risk of influenza-like illness (p < 0.005). Vaccine recipients had fewer episodes of fever, cough, muscle aches, runny nose (p < 0.001) and experience fewer sick days due to respiratory illness. Subjects who received influenza vaccination had clinically and statistically significant reductions in the attack rate of influenza-like illness. Our data support influenza vaccination of persons with chronic diseases and >50 year olds living in institutions.

Abnormal humoral immune response to influenza vaccination in pediatric type-1 human immunodeficiency virus infected patients receiving highly active antiretroviral therapy

Given that highly active antiretroviral therapy (HAART) has been demonstrated useful to restore immune competence in type-1 human immunodeficiency virus (HIV-1)-infected subjects, we evaluated the specific antibody response to influenza vaccine in a cohort of HIV-1-infected children on HAART so as to analyze the quality of this immune response in patients under antiretroviral therapy. Sixteen HIV-1-infected children and 10 HIV-1 seronegative controls were immunized with a commercially available trivalent inactivated influenza vaccine containing the strains A/H1N1, A/H3N2, and B. Serum hemagglutinin inhibition (HI) antibody titers were determined for the three viral strains at the time of vaccination and 1 month later. Immunization induced a significantly increased humoral response against the three influenza virus strains in controls, and only against A/H3N2 in HIV-1-infected children. The comparison of post-vaccination HI titers between HIV-1+ patients and HIV-1 negative controls showed significantly higher HI titers against the three strains in controls. In addition, post vaccination protective HI titers (defined as equal to or higher than 1:40) against the strains A/H3N2 and B were observed in a lower proportion of HIV-1+ children than in controls, while a similar proportion of individuals from each group achieved protective HI titers against the A/H1N1 strain. The CD4+ T cell count, CD4/CD8 T cells ratio, and serum viral load were not affected by influenza virus vaccination when pre- vs post-vaccination values were compared. These findings suggest that despite the fact that HAART is efficient in controlling HIV-1 replication and in increasing CD4+ T cell count in HIV-1-infected children, restoration of immune competence and response to cognate antigens remain incomplete, indicating that additional therapeutic strategies are required to achieve a full reconstitution of immune functions.

Risk factors for poor immune response to influenza vaccination in elderly people

Influenza vaccination of elderly people is efficacious and cost effective for the prevention of influenza and its complications. Some studies have pointed out low immunogenicity in this group. Health status has been poorly investigated as a risk factor that may influence the immune response to influenza vaccine. We established an immunization response study of a highly-matched elderly population in a nursing home. One-hundred-twenty subjects of Ashkenazian origin had their vaccine-induced antibody response assessed. Good response was obtained in 30.8 percent (37/120), and 31.7 percent (38/120) did not react. A lack of good response was found to be associated with dementia (P=0.016) in a multivariate analysis. In addition to dementia, malnutrition was frequently observed among poor responders, suggesting that these factors should be considered in vaccination studies. Chemoprophylaxis in addition to vaccination for elderly presenting dementia should be considered, particularly for those people living nursing homes.

La prevención de la influenza: recomendaciones para la temporada de 2005-2006 / Preventing influenza: recommendations for the 2005-2006 season

Influenza is a serious health problem worldwide due to the epidemics and pandemics that it periodically causes. The Advisory Committee on Immunization Practices (ACIP) of the United States of America recently published updated recommendations for influenza prevention and control for the 2005-2006 season. Many of these guidelines are of interest to the countries of the Region of the Americas, particularly those related to vaccination, which is the mainstay for preventing and controlling this disease. Various changes have been made in the recommendations that were published in 2004. First, the ACIP recommends vaccination against influenza for persons with any condition (e.g., cognitive dysfunction, spinal cord injury, seizure disorder, or other neuromuscular disorder) that can compromise respiratory function or make eliminating respiratory secretions difficult or that can increase the risk for aspiration. Second, the ACIP strongly recommends that all health care workers be vaccinated against influenza annually and encourages facilities that employ health care workers to vaccinate them by using approaches that maximize immunization rates. Third, the ACIP encourages the use of both available vaccines (inactivated and live, attenuated influenza vaccine (LAIV)) for eligible persons every influenza season, especially persons in recommended target groups. When inactivated virus vaccine is in short supply, the use of LAIV is especially encouraged, if feasible, for eligible persons (including health care workers) because such use might considerably increase the availability of inactivated virus vaccine for persons in high-risk groups. Fourth, the 2005-06 trivalent vaccine virus strains are A/California/7/2004 (H3N2)-like, A/New Caledonia/20/99 (H1N1)-like, and B/Shanghai/361/2002-like antigens. For the A/California/7/2004 (H3N2)-like antigen, manufacturers may use the antigenically equivalent A/ New York/55/2004 virus, and for the B/Shanghai/361/2002-like antigen, manufacturers may use the antigenically equivalent B/Jilin/20/2003 virus or B/Jiangsu/10/2003 virus.

Influenza surveillance in the Islamic Republic of Iran from 1991 to 2001

To better underst and the annual distribution of influenza virus in our country, we isolated and typed 45 viruses from 1043 patients with acute respiratory illnesses in a 10-year study conducted by the National Influenza Centre of the Islamic Republic of Iran. The seasonal distribution of influenza typically ran from November to April. Type A influenza was most common during the winters of 1991-92, 1997-98 and 2000-01 and type B influenza was most common during 1992-5 and 1996-97. Both type A and type B viruses circulated in 1995-96 and 1998-2000. A serological survey based on haemagglutination inhibition test confirmed our findings. The annual pattern of strains isolated was similar to the worldwide pattern during the same interval

Investigaçäo sorológica da influenza tipos A e B em estudantes universitários, Brasil / Serological investigation of influenza type A and B in university students

Levantamento sorológico realizado em 200 estudantes da Universidade de Säo Paulo, nos anos de 1984 e 1985, demonstrou ampla prevalência sorológica do vírus da influenza tipos A e B. Os anticorpos dos indivíduos foram detectados pela técnica de Hemólise Radial Simples (HRS), cujas médias aritméticas de títulos foram maiores entre as cepas dos subtipos (H1N1) e H3N2) do vírus da influenza tipo A, mais recentemente isoladas da populaçäo. Porém, com relaçäo ao tipo B, deste vírus, a situaçäo foi inversa, pois apesar da cepa B/Engl./847/73 ser a mais antiga incidente, revelou melhor reatogenicidade sobre as demais cepas avaliadas e de acordo com a doutrina do "Pecado original antigênico", é suposto que tenha sido responsável pela primo infecçäo na maioria do grupo investigado. A avaliaçäo sorológica dos subtipos do vírus influenza tipos A e B, desta populaçäo, revelou índices de anticorpos de baixos títulos HRS (2,5 a 3,5 mm) e de altos títulos (* 4,0 mm) que estäo relacionados ao menor e maior nível de proteçäo à infecçäo. Sendo que a capacidade individual da imunidade e da persistência de anticorpos contra o vírus, dependeram da atualidade e freqüência de exposiçäo à influenza.