Emerson Carraro

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% (37/120), and 31.7% (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.

Influenza virus and proteolytic bacteria co-infection in respiratory tract from individuals presenting respiratory manifestations

A role for proteolytic bacteria in the exacerbation of influenza virus has been shown in natural hosts such as pigs and humans. Four hundred seven samples were collected from the respiratory tract of individuals presenting clinical manifestations, during influenza season (2003-2005) in São Paulo City. The aim of this study was to evaluate the incidence of determined bacteria co-infecting virus in human respiratory tract. Tests, such as bacteriological, immunofluorescence (IF), RT/PCR and hemagglutination (HA) were used for bacterial and viral investigation. Thirty seven (9.09%) positive for influenza virus were screened by IF. The RT/PCR confirmed the presence of influenza virus in these samples. Bacterial and agar casein tests demonstrated that 18 (48.64%) individuals were infected with proteolytic bacteria such as Staphylococcus spp., Streptococcus spp. and Pseudomonas spp. Among these samples, 13 (35.13%) were co-infected with influenza A virus. Influenza type B, co-infecting bacteria were found in five (13.51%) samples. In vitro the S. aureus protease increased the influenza HA titer after contact for 30 min at 25 masculineC. Results revealed the occurrence of co-infection with proteolytic bacteria and influenza in the evaluated individuals. This finding corroborates that virus versus bacteria synergism could be able to potentiate respiratory infection, increasing damage to hosts.

Infections with human coronaviruses NL63 and OC43 among hospitalised and outpatient individuals in São Paulo, Brazil

The incidence and clinical features of human coronaviruses (HCoVs) among Brazilian patients with respiratory illness are not well known. We investigated the prevalence of HCoVs among Brazilian outpatients and hospitalised patients with respiratory illnesses during 2009 and 2010. To identify the HCoVs, pancoronavirus and species-specific reverse-transcriptase polymerase chain reaction assays were performed. Five of 394 samples were positive for HCoVs (1.2%): 1/182 (0.5%) outpatients and 4/212 (1.8%) hospitalised patients. The OC43 and NL63 HCoVs were identified. Two patients were admitted to the intensive care unit. Underlying chronic disease was reported in cases and one diabetic adult died. HCoVs can cause lower respiratory infections and hospitalisation. Patients with pre-existing conditions and respiratory infections should be evaluated for HCoV infections.

Influenza detection and subtyping by reverse transcriptase polymerase chain reaction-restriction fragment length polymorphism for laboratory surveillance in Brazil.

A duplex reverse transcriptase polymerase chain reaction-restriction fragment length polymorphism for influenza virus subtyping was applied to 412 patient samples. The assay was able to discriminate all 47 influenza A H1N1 and H3N2 viruses. This rapid technique assessed if positive samples were current circulating strains or an emergent one and could be used as the 1st test in prepandemic stages.

Surveillance of influenza A H1N1 2009 among school children during 2009 and 2010 in São Paulo, Brazil

INTRODUCTIONnInfluenza A H1N1 2009 is associated with a high morbidity rate among children around the world, including Brazil. This survey was conducted on samples of symptomatic children (< 12 years) to investigate the influenza virus as the etiological agent of respiratory infections in a day care school in a health facility during the first and second pandemic wave of H1N1 (2009-2010) in São Paulo, Brazil.nnnMETHODSnInfluenza infections were determined by real-time PCR in 34% (47/137) of children with a median age of 5 years (8 months - 12 years), from June to October 2009 and in 16% (14/85) of those with median age of 6 years (1-12 years), from March to November 2010.nnnRESULTSnIn general, most positive cases (64%) occurred in children aged 5-12 years, this age group was significantly the most affected (39.8%, p = 0.001, OR = 8.3, CI 95% 1.9-36.9). Wheezing was reported by 31% (19/61) and dyspnea by 23% (14/61) of the studied patients. An outbreak of influenza H1N1 with an attack rate of 35.7% among children (median age 6 years) was documented in April 2010, before the vaccination campaign against the pandemic virus was extended for children up to 5 years in Brazil.nnnCONCLUSIONSnTherefore, the study reinforces the recommendation to immunize school children to reduce the incidence of the disease.

Pandemic H1N1 illness prognosis: evidence from clinical and epidemiological data from the first pandemic wave in São Paulo, Brazil

OBJECTIVES: The pandemic of 2009 H1N1 influenza A emerged in February 2009, with high morbidity and mortality, and rapidly spread globally. São Paulo was among the most affected areas in Brazil. This study compares the clinical and epidemiological characteristics of influenza-like illness between outpatients and hospitalized patients and evaluates the impact of oseltamivir therapy on the outcome of 2009 H1N1 influenza A patients. METHODS: This is a case series study comparing the clinical and epidemiological characteristics of influenza-like illness between outpatients attended at Hospital São Paulo in August 2009 (the peak of the first pandemic wave) and those patients hospitalized between May and September 2009 (the entire first pandemic wave). RESULTS: The 1651 patients evaluated were predominantly female (927×686, p<0.001) and aged 31.71±16.42 years, with 148 reporting chronic pulmonary disease. Dyspnea was presented by 381 (23.4%) patients and was more frequent among those aged 30 years or more (p<0.001). Hospitalization occurred at 3.73±2.85 days, and antiviral treatment started 2.27±2.97 days after the onset of first symptoms. A delay of more than 5 days in starting oseltamivir therapy was independently associated with hospitalization (p<0.001), a stay in the ICU (p<0.001) and a higher risk of dying (ORu200a=u200a28.1, 95% CI 2.81-280.2, pu200a=u200a0.007). CONCLUSION: The 2009 pandemic of H1N1 influenza A affected young adults, presented a significant disease burden and produced severe cases with a significant fatality rate. However, promptly starting specific therapy improved the outcome.

Human rhinovirus infections in symptomatic and asymptomatic subjects

The role of rhinovirus asymptomatic infections in the transmission among close contacts subjects is unknown. We tested health care workers, a pair of one child and a family member and immunocompromised patients (n =191). HRV were detected on 22.9% symptomatic and 3.6% asymptomatic cases suggesting lower transmission among contacts.

Rhinovirus detection using different PCR-based strategies

Human rhinoviruses (HRVs) are the major cause of the common cold. HRVs were recently reclassified into the Enterovirus genus (HEV) in the Picornaviridae family. HRVs and other members of the HEV genus share many common features, including sense RNA genomes and partial nucleotide sequence identity. The aim of this study was to evaluate different HRV detection strategies. Samples from adults with acute respiratory infection (n = 291) who were treated in Sao Paulo Hospital (2001-2003) were tested using three assays. The first assay detected picornaviruses by RT-PCR and hybridization, the second detected rhinoviruses using RT-PCR/sequencing, and the third differentiated HRV from HEV using duplex semi-nested-RT-PCR. Analysis of the results obtained from the first two strategies revealed 83% concordance. Discordant samples were then evaluated by the third protocol, and 82% were negative. The picornavirus detection protocol was more sensitive but less specific than the rhinovirus detection protocols. The semi-nested protocol utilized in the present study was less sensitive and was not useful in differentiating HRV from HEV. Sequencing assays examining different genes would address the best strategy of confirming rhinovirus and enterovirus infections.

Genotipagem do citomegalovírus humano para pesquisa de resistência primária aos antivirais em transplantados renais

O objetivo do estudo foi investigar a ocorrencia de cepas de citomegalovirus humano (HCMV) com resistencia primaria aos antivirais utilizados na terapeutica de pacientes transplantados renais. Para isso empregou-se um metodo de triagem por reacao em cadeia de polimerase (PCR) e polimorfismo de tamanho de fragmentos de restricao (RFLP) capaz de detectar mutacoes especificas nos genes UL97 e UL54 relacionadas com resistencia antiviral. Foram coletadas amostras (sangue, saliva e urina) de 20 pacientes transplantados renais no momento do diagnostico da infeccao pelo HCMV e sem terapia antiviral previa. Embora nao tenham sido encontradas cepas de HCMV com nenhuma das mutacoes estudadas, a metodologia empregada demonstrou-se rapida e eficaz na analise dos genes virais das diferentes amostras testadas. A ausencia de resistencia primaria no presente estudo nao descarta a possibilidade de esse evento ocorrer futuramente no Brasil, uma vez que o emprego das drogas antivirais tem se disseminado em todo o mundo. Sugerimos, entao, a aplicacao da metodologia de PCR/RFLP na investigacao de resistencia do HCMV aos antivirais.

Comparison of a rapid cytomegalovirus pp65 antigenemia assay revealed by immunofluorescence to an in-house assay revealed by immunoperoxidase for diagnosis in solid organ transplant recipient patients

Cytomegalovirus (CMV) antigenemia is still one of the two major assays available for diagnosis and monitoring of CMV infections. A commercial rapid test recently available in Brazil for quantification of human cytomegalovirus pp65 antigenemia revealed by immunofluorescence technique was compared with the original in-house method revealed by immunoperoxidase in patients receiving solid organ transplants. Of 80 blood samples tested for CMV antigenemia, 34 (42.5%) were positive: commercial assay detected 33 (97%) and in-house assay detected 20 (58.8%) samples. The numbers of positive cells in the two assays were different, with a median of 4.5 and 12 positive cells obtained by in-house and commercial kit, respectively. Discrepancies between assays occurred in 15 specimens from patients with low-grade antigenemia (median 6 positive cells). The assay-time was reduced in approximately 50% compared to in-house methodology. In conclusion, besides comparable results obtained for both assays, the commercial antigenemia assay provides more rapid and sensitive results.