Risk factors for severe disease in pediatric respiratory syncytial virus infections.

OBJECTIVES: To assess factors associated with the risk of severe disease in children aged 5 years or younger with laboratory-confirmed respiratory syncytial virus (RSV) infection. STUDY DESIGN: We conducted a nationwide retrospective cohort study in Mexico. METHODS: Eligible participants included children aged 5 years or younger with laboratory-confirmed RSV infection January 1, 2023, and May 15, 2024. We collected relevant clinical and epidemiological data. Risk ratios (RR) and 95% confidence intervals (CI) were employed to identify factors associated with the risk of severe disease, characterized by clinical and radiographic evidence of bronchiolitis or pneumonia requiring hospital admission. RESULTS: Data from 2022 children were analyzed and the overall risk of severe disease was 21.0% (n = 424/2022). In multiple generalized linear regression analysis, a personal history of immunosuppression (due to any cause) showed a protective effect (RR = 0.14, 95% CI 0.05-0.42, P = 0.001) against severe RSV disease, while an increased risk was documented for each additional day elapsed between the date of symptom onset and the date of seeking healthcare RR = 1.06, 95% CI 1.02-1.10, P = 0.004). CONCLUSION: These findings provide insights into risk stratification and suggest specific directions for future research. This information informs the development of targeted intervention strategies to mitigate the impact of RSV infections in this vulnerable population.

Variability in the Timing of Respiratory Syncytial Virus Epidemics in Guatemala, 2008-2018.

BACKGROUND: The description of local seasonality patterns in respiratory syncytial virus (RSV) incidence is important to guide the timing of administration of RSV immunization products. METHODS: We characterized RSV seasonality in Guatemala using the moving epidemic method (MEM) with absolute counts of RSV-associated acute respiratory infections (ARI) from hospital surveillance in Santa Rosa and Quetzaltenango departments of Guatemala. RESULTS: From Week 17 of 2008 through Week 16 of 2018, 8487 ARI cases tested positive for RSV by rRT-PCR. Season onsets varied up to 5 months; early seasons starting in late May to early August and finishing in September to November were most common, but late seasons starting in October to November and finishing in March to April were also observed. Both epidemic patterns had similar durations ranging from 4 to 6 months. Epidemic thresholds (the levels of virus activity that signal the onset and end of a seasonal epidemic) calculated prospectively using previous seasons' data captured between 70% and 99% of annual RSV detections. Onset weeks differed by 2-10 weeks, and offset weeks differed by 2-16 weeks between the two surveillance sites. CONCLUSIONS: Variability in the timing of seasonal RSV epidemics in Guatemala demonstrates the difficulty in precisely predicting the timing of seasonal RSV epidemics based on onset weeks from past seasons and suggests that maximal reduction in RSV disease burden would be achieved through year-round vaccination and immunoprophylaxis administration to at-risk infants.

Respiratory syncytial virus infection in children during SARS-CoV-2 pandemic at a referral center in Rio de Janeiro, Brazil

ABSTRACT Objective: In order to study the scenario of respiratory infections in pediatrics after the emergence of SARS-CoV-2 in Brazil, this study aimed to compare characteristics of children admitted for SARS or upper airway infection caused by either RSV or SARS-CoV-2. Methods: This was a cross-sectional study involving children up to 48 months of age admitted to a tertiary pediatric hospital with a diagnosis of SARS or upper airway infection between April of 2020 and April of 2021. Respiratory secretion samples were collected 2-5 days after hospitalization, and antigen/PCR tests for viral etiologies were performed. In this analysis, patients with laboratorial diagnosis of SARS-CoV-2 and/or RSV were selected, and their clinical and epidemiological characteristics were compared using logistic regression. Results: Our sample initially comprised 369 participants. SARS-CoV-2 and RSV infections were confirmed in 55 (15%) and 59 children (16%), respectively. Mean age was 12 months (0-48 months), and 47 were female. The following characteristics were significantly more frequent in patients with RSV when compared with those with COVID-19: younger age (OR = 0.94; 95% CI: 0.90-0.98); lower frequency of fever (OR = 0.18; 95% CI: 0.05-0.66); and more frequent upper airway symptoms: cough (OR = 7.36; 95% CI: 1.04-52.25); and tachypnea (OR = 6.06; 95% CI: 1.31-28.0). Conclusions: Children with RSV-related SARS were younger, had lower frequency of fever at admission, but had a higher frequency of signs of upper airway infection and lower systemic inflammation when compared with children hospitalized for COVID-19 during the first year of the pandemic.

Novedades en el calendario de vacunas de Argentina. Primera parte: virus sincicial respiratorio / News in Argentina's vaccine schedule. Part one: respiratory syncytial virus

A fines de 2023 la autoridad sanitaria de Argentina realizó modificaciones en el Calendario Nacional obligatorio, que serán implementadas en forma progresiva durante 2024. Este artículo está enfocado en la introducción de la vacuna contra el virus sincicial respiratorio en las personas embarazadas que cursan las semanas 32 a 36 de gestación durante la temporada de circulación del virus. (AU)

At the end of 2023, the Argentine health authority modified the mandatory National Calendar, which will be implemented progressively during 2024. This article focuses on the introduction of the vaccine against respiratory syncytial virus in pregnant women in the 32nd to 36th weeks of gestation during the season of the virus's circulation. (AU)

Temporal-spatial analysis of hospitalizations for bronchiolitis in Brazil: prediction of epidemic regions and periods for immunization against the Respiratory Syncytial Virus / Análise temporal-espacial de hospitalizações por bronquiolite no Brasil: previsão das regiões e períodos epidêmicos para imunização contra o vírus sincicial respiratório

Abstract Objective: Due to the high cost and short term of passive immunization against the respiratory syncytial virus, the main virus causing acute viral bronchiolitis, predicting epidemic regions and epidemic months is extremely important. The objective of this study is to identify both the month when the seasonal peak begins and Brazilian regions and states with the highest incidence of monthly hospitalizations due acute viral bronchiolitis. Methods: Based on data obtained from DATASUS, monthly hospitalization rates due acute viral bronchiolitis were calculated for every 10,000 live births to children under 12 months of age in all Brazilian states and the Federal District between 2000 and 2019. Seasonal autoregressive integrated moving average models were estimated to forecast monthly hospitalization rates in 2020. Results: A higher incidence of hospitalizations was found for male children, especially under six months of age. As for Brazilian regions, between 2000 and 2019, the South region registered the highest incidence of hospitalizations, followed by the Southeast, Midwest, North and Northeast regions, in this order. Considering the seasonal peak, the period between March and July 2020 comprised the highest expected hospitalization rates. Conclusions: Palivizumab is suggested to be started between February/March and June/July for most Brazilian states, with the exception of Rio Grande do Sul, which, in addition to presenting the highest rates of hospitalizations for acute viral bronchiolitis per 10,000 live births, has the longest seasonal peak between May and September.

RESUMO Objetivo: Em razão do alto custo e do curto prazo da imunização passiva contra o vírus sincicial respiratório, principal vírus causador de bronquiolite viral aguda, a previsão das regiões e meses epidêmicos é extremamente importante. Objetiva-se identificar o mês de início do pico sazonal e as regiões e Estados brasileiros de maior incidência de hospitalizações mensais por bronquiolite viral aguda. Métodos: Com dados obtidos no Departamento de Informática do Sistema Único de Saúde do Brasil, foram calculadas as taxas mensais de hospitalizações por bronquiolite viral aguda a cada 10 mil nascidos vivos de crianças com idade inferior a 12 meses, em todos os Estados brasileiros e no Distrito Federal, no período entre 2000 e 2019. Modelos sazonais autorregressivos integrados e de médias móveis foram estimados para a previsão das taxas mensais de hospitalizações em 2020. Resultados: Verificou-se maior incidência de hospitalizações em crianças do sexo masculino, principalmente naquelas com idade inferior a seis meses. Em relação às regiões brasileiras, entre 2000 e 2019, a Região Sul apresentou a maior incidência de hospitalizações, seguida pelas Regiões Sudeste, Centro-Oeste, Norte e Nordeste, respectivamente. Quanto ao pico sazonal, o período entre março e julho de 2020 compreende as maiores taxas de hospitalizações previstas. Conclusões: Sugere-se o início da administração do Palivizumab entre fevereiro/março e junho/julho para a maioria dos Estados brasileiros, com exceção do Rio Grande do Sul, que, além de apresentar as maiores taxas de hospitalizações por bronquiolite viral aguda a cada 10.000 nascidos vivos, possui o pico sazonal de maior duração entre maio e setembro.

Infección respiratoria polimicrobiana: un caso de colonización multirresistente y coinfección viral en un lactante

Se presenta el caso de un lactante de 38 semanas ingresado con distrés respiratorio a un nosocomio al norte del Perú. Tras intubación y conexión a ventilación mecánica, se administró tratamiento antimicrobiano y sedoanalgesia. Durante la hospitalización, el paciente presentó fiebre, tos con expectoración quintosa, rubicundez facial y desaturación. Se observó edema en párpados, manos y pies, pero la perfusión tisular se mantuvo adecuada. En el cuarto día, sufrió convulsión febril, sibilancias respiratorias y oliguria con hematuria. Se realizaron cambios en el tratamiento y se administraron transfusiones. Al día 7, con apoyo del panel de PCR múltiple (FilmArray®) para el diagnóstico etiológico de enfermedades infecciosas respiratorias, se diagnosticó colonización/infección por Acinetobacter baumanni multirresistente, la cual se acompañó con la detección de Serratia marcescens y virus sincicial respiratorio. Tras una estancia prolongada se logró la extubación exitosa el día 10. El día 24, el paciente fue dado de alta sin fiebre, signos vitales estables y sin requerir oxígeno, solo tratamiento para las convulsiones.

A case is presented of a 38-week-old infant admitted with respiratory distress to a hospital in northern Perú. After intubation and connection to mechanical ventilation, antimicrobial treatment and sedoanalgesia were administered. During hospitalizaron, the patient experienced fever, cough with quintose expectoration, facial rubor, and desaturation. Edema was observed in the eyelids, hands, and feet, but tissue perfusion remained adequate. On the fourth day, the patient had a febrile seizure, respiratory wheezing, and oliguria with hematuria. Treatment changes were made, and transfusions were administered. On the seventh day, using the FilmArray® multiplex PCR panel for etiological diagnosis of respiratory infectious diseases, colonization/infection by multidrug-resistant Acinetobacter baumanni was diagnosed, accompanied by the detection of Serratia marcescens and respiratory syncytial virus. After a prolonged stay, successfu extubation was achieved on day 10. On day 24, the patient was discharged without fever, stable vital signs, and without requiring oxygen only treatment for seizures.

Assessment of Peak Inspiratory Flow in Young Infants with Acute Viral Bronchiolitis: Physiological Basis for Initial Flow Setting in Patients Supported with High-Flow Nasal Cannula.

OBJECTIVE: To assess the inspiratory demand in young infants with acute viral bronchiolitis to provide a physiological basis for initial flow setting for patients supported with high flow nasal cannula. STUDY DESIGN: Prospective study in 44 infants up to 6 months old with acute viral bronchiolitis, admitted to a pediatric intensive care unit from November 2017 to March 2019. Airflow measurements were performed using spirometry. The primary endpoint was the inspiratory demand as measured by peak tidal inspiratory flow (PTIF). The secondary endpoints were the relationships determined between PTIF, patient weight, and disease severity. RESULTS: Median (Q25-Q75) age and weight of the patients were 37 (20-67) days and 4.3 (3.5-5.0) kg, respectively. Mean PTIF was 7.45 (95% CI 6.51-8.39, min-max: 2.40-16.00) L/minute. PTIF indexed to weight was 1.68 (95% CI 1.51-1.85, min-max: 0.67-3.00) L/kg/minute. PTIF was <2.5 L/kg/minute in 89% (95% CI 75-96) of infants. PTIF was correlated with weight (ρ= 0 .55, P < .001) but not with markers of disease severity, including modified Woods clinical asthma score, Silverman-Andersen score, respiratory rate, fraction of inspired oxygen, and PCO2. CONCLUSIONS: High flow nasal cannula therapy is used commonly to support infants with acute viral bronchiolitis. The efficiency of the device is optimal if the flow setting matches the patient's inspiratory demand. According to our results, a flow rate of <2.5 L/kg/minute would be appropriate in most situations.

Seasonality and coinfection of bronchiolitis: epidemiological specificity and consequences in terms of prophylaxis in tropical climate.

OBJECTIVE: To describe the viruses involved, seasonality and coinfection in hospitalised children with suspected bronchiolitis. METHODS: Over the period 1/07/2007 to 31/12/2008, all children hospitalised for bronchiolitis in the paediatric ward were prospectively included, and had respiratory syncytial virus (RSV) screenings. We retrospectively tested all samples for RSVA, RSVB, rhinovirus (RV), human metapneumovirus, parainfluenza 1, 2, 3, 4, influenza A and influenza B. RESULTS: 198 children were tested, and 23% were negative for all viruses. RSVA was predominant in 2008 (64% of all viruses) and RSVB in 2007 (66% of all viruses). RV was frequent during both seasons (24% of all viruses). Flu was not found during the study period. Virus distribution was similar regardless of season or age, and identical to typical patterns in temperate countries. Coinfections were less frequent than in temperate regions because respiratory virus seasons seem to be better separated. The bronchiolitis season started in August and finished in December with a peak in October. CONCLUSION: The specific seasonality of bronchiolitis infection requires palivizumab prophylaxis starting in early July for high-risk infants.

OBJECTIF: Décrire les virus impliqués, la saisonnalité et la coinfection chez les enfants hospitalisés avec une suspicion de bronchiolite. MÉTHODES: Au cours de la période du 01/07/2007 au 31/12/2008, tous les enfants hospitalisés pour bronchiolite dans le service de pédiatrie ont été prospectivement inclus et soumis à un dépistage du virus respiratoire syncytial (VRS). Nous avons testé rétrospectivement tous les échantillons pour RSVA, RSVB, rhinovirus (RV), métapneumovirus humain, Parainfluenza 1, 2, 3, 4, Influenza A, et Influenza B. RÉSULTATS: 198 enfants ont été testés et 23% étaient négatifs pour tous les virus. RSVA était prédominant en 2008 (64% de tous les virus) et RSVB en 2007 (66% de tous les virus). RV était fréquent pendant les deux saisons (24% de tous les virus). La grippe n'a pas été trouvée pendant la période d'étude. La distribution des virus était similaire quelle que soit la saison ou l'âge, et identique aux modèles typiques dans les pays tempérés. Les coinfections étaient moins fréquentes que dans les régions tempérées car les saisons virales respiratoires semblent mieux séparées. La saison des bronchiolites a commencé en août et s'est terminée en décembre avec un pic en octobre. CONCLUSION: La saisonnalité spécifique de l'infection bronchiolite nécessite une prophylaxie au palivizumab débutant en juillet pour les nourrissons à haut risque.

Análise da prevalência de vírus respiratórios em crianças atendidas em um hospital universitário do sul de Minas Gerais / Analysis of respiratory virus prevalence in assisted children in a university hospital of southern of minas gerais

INTRODUÇÃO: As infecções respiratórias virais são doenças de alta incidência no nosso meio. Os vírus circulam durante todo ano, todavia, a incidência destas infeccões aumentam com a sazonalidade. Grande parte destas infecções ocorrem em crianças por serem mais susceptíveis do ponto de vista imunológico. OBJETIVO: Analisar a prevalência dos patógenos virais nas infecções respiratórias em crianças de 0 a 9 anos no Hospital das Clinicas Samuel Libanio(HCSL), Pouso Alegre - MG. MÉTODOS: Foi realizada uma revisão sistemática dos dados coletados a partir de aspirados de orofaringe, para pesquisa de vírus pela equipe da Comissão de Controle de Infecções Hospitalares (CCIH), entre os anos de 2010 e 2014. RESULTADOS: Foram analisados 310 amostras e cerca de 26,4% foram positivas para algum vírus. O vírus sincicial respiratório (VSR) foi o mais prevalente nas crianças menores de um e também na faixa etária de 1 a 4 anos (25,3% e 11,1 %, respectivamente), estatisticamente significante (p<0,001). Já no grupo entre 5 a 9 anos prevaleceu o virus Influenza A H1N1 com 13,8%. CONCLUSÃO: As infecções virais contribuem para um alto número de hospitalizações que oneram o serviço público de saúde, principalmente na faica etária pediátrica. Deste modo, medidas preventiva como campanhas de vacinação devem continuar a ser incentivadas, de preferência abrangendo os vírus mais prevalentes para uma determinada faixa etária. (AU)

Introduction: Viral respiratory infections are of high incidence diseases in our midst. Viruses circulate throughout the year, however, the incidence of these infections increase with seasonality. Most of these infections occur in children because they are more likely immunologically. Objective: To analyze the prevalence of viral pathogens in respiratory infections in children aged 0 to 9 years old at the Samuel Libânio Clinical Hospital, Pouso Alegre-MG. Methods: A systematic review of data collected from aspirates oropharynx was performed to search for viruses by the Commission's Team of Nosocomial Infection Control between the years 2010 and 2014. Results: 310 samples were analyzed and about 26.4% of the samples were positive for a virus. Respiratory syncytial virus (RSV) was the most prevalent in children under one year old and also in the age group 1-4 years (25.3% and 11.1%, respectively), statistically significant (p<0.001). In the group between 5 and 9 years prevailed the virus Influenza A H1N1 with 13.8%. Conclusions: Viral infections contribute to a high number of hospitalizations that burden the public health system, especially in the pediatric age group. Thus, preventive measures such as vaccination campaigns should continue to be encouraged, preferably covering the most prevalent virus for a certain age group (AU)

Infección por virus respiratorios en adultos hospitalizados en un Servicio de Medicina Interna / Respiratory virus infections in adult patients hospitalized in an internal medicine unit

Background: Respiratory viral infections (RVi) can be associated with a wide range of clinical manifestations. Aim: To investigate the frequency and clinical manifestations of RVi among adult patients during winter hospitalizations. Patients and Methods: All patients admitted to the hospital with flu like disease and those with fever or exacerbation of any underlying disease during hospitalization without an evident cause, were prospectively enrolled. A direct immunofluorescence (DIF) of nasopharyngeal aspirate for influenza A (IA) and B, parainfluenza 1, 2 and 3, adenovirus, respiratory syncytial virus (RSV) and metapneumovirus, was performed. Epidemiological and clinical data were recorded. Results: Between May and September 2012, 975 adults were admitted to the Internal Medicine Unit of Puerto Montt Hospital and in 128 (13%) patients, DIF was carried out. DIF was positive in 44 patients (34%) aged 65 ± 20 years, 68.2% females, corresponding to 4.5% of total hospitalizations. Eighty six percent of the latter had at least one co-morbidity, mainly asthma and chronic respiratory diseases in 34.1%, diabetes in 29.5%, cardiac problems in 25% and congestive heart failure in 20.5%. The most common RVi were RSV (n = 21, 48%) and IA (n = 17, 39%). Six patients had a nosocomial RVi. Patients infected with IA had a significantly higher frequency of fever and bronchial hyper reactivity than those infected with RSV. RVi were associated with exacerbation of underlying disease in 62% of cases and pneumonia in 27%. Two patients had a viral pericarditis. Conclusions: RVi are an important cause of adult morbidity and their detection should be routine in adult patients hospitalized during winter.

Respiratory syncytial virus circulation in seven countries with Global Disease Detection Regional Centers.

BACKGROUND: Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infections in young children globally, with the highest burden in low- and middle-income countries where the association between RSV activity and climate remains unclear. METHODS: Monthly laboratory-confirmed RSV cases and associations with climate data were assessed for respiratory surveillance sites in tropical and subtropical areas (Bangladesh, China, Egypt, Guatemala, Kenya, South Africa, and Thailand) during 2004-2012. Average monthly minimum and maximum temperatures, relative humidity, and precipitation were calculated using daily local weather data from the US National Climatic Data Center. RESULTS: RSV circulated with 1-2 epidemic periods each year in site areas. RSV seasonal timing and duration were generally consistent within country from year to year. Associations between RSV and weather varied across years and geographic locations. RSV usually peaked in climates with high annual precipitation (Bangladesh, Guatemala, and Thailand) during wet months, whereas RSV peaked during cooler months in moderately hot (China) and arid (Egypt) regions. In South Africa, RSV peaked in autumn, whereas no associations with seasonal weather trends were observed in Kenya. CONCLUSIONS: Further understanding of RSV seasonality in developing countries and various climate regions will be important to better understand the epidemiology of RSV and for timing the use of future RSV vaccines and immunoprophylaxis in low- and middle-income countries.

Afectación cardíaca en el curso de infecciones respiratorias agudas virales: reporte preliminar / Cardiac involvement during acute viral respiratory infections: preliminary report

Las infecciones respiratorias agudas bajas virales constituyen una de las causas más importantes de enfermedad y muerte en niños en todo el mundo. En Uruguay las infecciones respiratorias agudas constituyen la causa más frecuente de admisión hospitalaria en los meses fríos y una causa prevalente de ingreso a cuidados intensivos. La afectación miocárdica ha sido descrita como complicación determinante en la evolución de la enfermedad. Objetivos: conocer la prevalencia y gravedad de la afectación cardíaca en el curso de las infecciones respiratorias agudas bajas virales y evaluar la utilidad de la troponina T para despistar compromiso miocárdico. Material y métodos: estudio descriptivo prospectivo. Se incluyeron lactantes portadores de infecciones respiratorias agudas bajas virales admitidas al hospital. Se realizó en todos los pacientes estudio radiológico de tórax, ECG, test de troponina T sérica y ecocardiograma. Se realizó seguimiento a los que presentaron afectación en el ECG, ECO o en el test de troponina. Resultados: se incluyeron 80 pacientes. El virus sincicial respiratorio (VRS) fue la etiología en el 53%. El ECG evidenció alteraciones inespecíficas de la repolarización en el 17% de los casos Se describió la presencia de derrame pericárdico en el 9% de los casos. Estas alteraciones no se asociaron con la gravedad ni la etiología. La troponina estuvo aumentada en el 4% sin asociaciones significativas con las variables analizadas. La CPK en estos pacientes fue normal. No hubo muertes en esta muestra. Conclusiones: se evidenciaron frecuentes alteraciones cardíacas por el ECG y el ECO que no se asociaron con requerimiento de cuidados intensivos o ventilación mecánica. La troponina estuvo aumentada en el 4% de los casos, lo que se considera una prevalencia menor a lo referido en la bibliografía, lo que no se vinculó con la evolución de los pacientes.

Acute viral respiratory infections are one of the most important causes of illness and death in children around the world. In Uruguay, acute respiratory infections are the cause of hospital admissions in the cold months and a prevalent admission cause to be admitted in intensive care. Myocardial involvement has been described as a major complication in the evolution of the disease. Objectives: to know the prevalence and severity of heart illness in the course of the low viral load acute respiratory infections and assess the usefulness of troponin T to find myocardial compromise. Material and methods: prospective descriptive study. We included IRABV carriers, admitted to the hospital, of up to two years. All RX chest, ECG, troponin T serum and Echocardiogram tests performed. Follow-up to those which presented affectation ECG, ECO or troponin test took place. Results: 80 patients were included. VRS was the etiology in 53%. The ECG evidenced unspecific alterations of the repolarization in 17%. The presence of pericardial effusion was described in 9% of cases. These alterations were not associated with the seriousness or etiology. Troponin was increased by 4% without significant association with the analyzed variables. CPK in these patients was normal. There were no deaths in this sample. Conclusions: frequent heart alterations by the ECG and ECO became apparent but were not associated with requirements of intensive care or mechanical ventilation. Troponin was increased in 4 per cent of cases but it was not linked to the evolution of patients.

Pneumonias virais: aspectos epidemiológicos, clínicos, fisiopatológicos e tratamento: [revisão] / Viral pneumonia: epidemiological, clinical, pathophysiological and therapeutic aspects: [review]

As infecções do trato respiratório são as formas de infecção mais comuns que afetam o homem e, dentre essas, predominam as de causa viral. Os vírus também podem acometer o trato respiratório baixo, causando bronquiolite, bronquite e pneumonia. Neste artigo de revisão, objetivamos mostrar aspectos epidemiológicos, fisiopatológicos, clínicos e do tratamento das pneumonias comunitárias por vírus. Essas pneumonias costumam ser causadas por vírus influenza A e B; parainfluenza 1, 2 e 3; vírus respiratório sincicial; e adenovírus. Também são apresentados aqui os hantavírus, metapneumovírus e rinovírus causando pneumonia.

In humans, the most common types of infection are respiratory tract infections, among which viral infections predominate. Viruses can also infect the low respiratory tract, causing bronchiolitis, bronchitis and pneumonia. The objective of this review article was to show epidemiological, pathophysiological, clinical and therapeutic aspects of viral community-acquired pneumonia. These types of pneumonia are commonly caused by influenza A and B; parainfluenza 1, 2 and 3; respiratory syncytial virus; or adenovirus. We also address the types of pneumonia caused by hantaviruses, metapneumoviruses and rhinoviruses.