Swine-origin influenza A (H1N1) in Indian children

An Eight-Year Profile of Children with Influenza A(H1N1) in a Large Hospital in India

As influenza virus A(H1N1) continues to circulate, reports from India have documented mainly respiratory involvement in children. This retrospective chart review of children at a medical college found that from August 2009 to July 2017, 855 children aged 3 months to 15 years had H1N1 influenza of whom 310 (36.3%) were admitted and 29 (9.4% admissions) died. In 2009-12, 76.5% patients presented in August-October but from 2015 to 2017, 89.3% came in January-March. The proportion of under-fives increased from 54.0% in 2009-10 to 77.7% in 2015-17. Among admitted children, 82.6% were under 5 years, 96.1% had respiratory symptoms and 11% had seizures. Six children had encephalopathy of whom four died; two survivors had severe neurological sequelae. Other features included gastroenteritis, otitis media, myositis and hepatitis. Complications included shock (10.7%) and acute respiratory distress syndrome (6.1%). Evidence of bacterial/fungal infection was present in 71 (22.9%). Oxygen was required by 123 children (39.7%), high-dependency/intensive care by 47 (15.2%), 17 (5.5%) received high-flow oxygen and 29 (9.4%) required mechanical ventilation. There were no significantly increased odds of needing intensive care or of dying in children with underlying diseases or among different age groups but those with underlying central nervous system (CNS) diseases had higher odds of needing high-dependency/intensive care [odds ratio (OR) 2.35, p = 0.046]. Significantly, children with CNS symptoms had nearly seven times higher odds of needing mechanical ventilation (OR 6.85, p < 0.001) and over three times higher odds of dying (OR 3.31, p = 0.009). Lay summaryH1N1 Influenza ("swine flu") emerged as a global pandemic in 2009 and continues to affect children all over the world. This review of records from a medical college hospital in southern India found that 855 children aged 3 months to 15 years came with H1N1 influenza over 8 years from August 2009 to July 2017. In 2009-12, over three-quarters of them presented in the rainy season but from 2015-17, almost 90% came in the winter and spring, suggesting a change in the seasonality of the outbreaks, which could impact the choice of dates for annual influenza vaccination. The proportion under 5 years of age increased from 54% in 2009-10 to 78% in 2015-17, suggesting possible immunity in children exposed to earlier outbreaks. Over a third of the children needed admission of whom almost 40% needed oxygen, one-sixth needed high-dependency/intensive care and 1 in 11 admitted children died, emphasizing the severity of this disease. While most children had respiratory symptoms, all organs of the body were affected; 11% of those admitted had seizures and 6 had encephalitis. Children admitted with central nervous system symptoms had an almost 7-fold higher risk of needing high-dependency/intensive care and an over 3-fold higher risk of dying.

Distinctive clinical and laboratory features of COVID-19 and H1N1 influenza infections among hospitalized pediatric patients

BACKGROUND

It had been documented in many studies that pediatric coronavirus disease 2019 (COVID-19) is characterized by low infectivity rates, low mortalities, and benign disease course. On the other hand, influenza type A viruses are recognized to cause severe and fatal infections in children populations worldwide. This study is aimed to compare the clinical and laboratory characteristics of COVID-19 and H1N1 influenza infections.

METHODS

A retrospective study comprising 107 children hospitalized at Abha Maternity and Children Hospital, Southern region of Saudi Arabia, with laboratory-confirmed COVID-19 and H1N1 influenza infections was carried out. A complete follow-up for all patients from the hospital admission until discharge or death was made. The clinical data and laboratory parameters for these patients were collected from the medical records of the hospital.

RESULTS

Out of the total enrolled patients, 73 (68.2%) were diagnosed with COVID-19, and 34 (31.8%) were diagnosed with H1N1 influenza. The median age is 12 months for COVID-19 patients and 36 months for influenza patients. A relatively higher number of patients with influenza had a fever and respiratory symptoms than COVID-19 patients. In contrast, gastrointestinal symptoms were observed in a higher number of COVID-19 patients than in influenza patients. A statistically significant increase in white cell counts is noted in COVID-19 but not in influenza patients (P < 0.05). There are no obvious variations in the mean period of duration of hospitalization between COVID-19 and influenza patients. However, the total intensive care unit length of stay was longer for influenza compared to COVID-19 patients.

CONCLUSIONS

A considerable number of children infected with COVID-19 and H1N1 influenza were noted and reported in this study. There were no significant variations in the severity of the symptomatology and laboratory findings between the two groups of patients. Significant differences between these patients in some hospitalization factors and diagnosis upon admission also were not observed. However, more severe clinical manifestations and serious consequences were observed among pediatric patients hospitalized with influenza infections than among those with COVID-19.

Can we distinguish respiratory viral infections based on clinical features? A prospective pediatric cohort compared to systematic literature review

Studies have shown that the predictive value of “clinical diagnoses” of influenza and other respiratory viral infections is low, especially in children. In routine care, pediatricians often resort to clinical diagnoses, even in the absence of robust evidence‐based criteria.

We used a dual approach to identify clinical characteristics that may help to differentiate infections with common pathogens including influenza, respiratory syncytial virus, adenovirus, metapneumovirus, rhinovirus, bocavirus‐1, coronaviruses, or parainfluenza virus: (a) systematic review and meta‐analysis of 47 clinical studies published in Medline (June 1996 to March 2017, PROSPERO registration number: CRD42017059557) comprising 49 858 individuals and (b) data‐driven analysis of an inception cohort of 6073 children with ILI (aged 0‐18 years, 56% male, December 2009 to March 2015) examined at the point of care in addition to blinded PCR testing. We determined pooled odds ratios for the literature analysis and compared these to odds ratios based on the clinical cohort dataset.

This combined analysis suggested significant associations between influenza and fever or headache, as well as between respiratory syncytial virus infection and cough, dyspnea, and wheezing. Similarly, literature and cohort data agreed on significant associations between HMPV infection and cough, as well as adenovirus infection and fever. Importantly, none of the abovementioned features were unique to any particular pathogen but were also observed in association with other respiratory viruses.

In summary, our “real‐world” dataset confirmed published literature trends, but no individual feature allows any particular type of viral infection to be ruled in or ruled out. For the time being, laboratory confirmation remains essential. More research is needed to develop scientifically validated decision models to inform best practice guidelines and targeted diagnostic algorithms.

Influenza in Children

In children, influenza is one among the commonest causes of acute respiratory illness and loss of school days. Influenza A, B, and C are 3 types of viruses responsible for illness. Type A virus has many subtypes based on antigens but Type B and Type C viruses have no known subtypes. Currently, influenza A/H1N1, A/H3N2, and influenza type B viruses are circulating in humans. Transmission of influenza occurs through droplets from infected person or through direct contact with person or fomites. Clinically, influenza is characterized by acute onset fever, chills, running nose, cough, sore throat, headache and myalgia. Mostly, febrile illness lasts for 3-4 d with resolution of disease in 7-10 d. Confirmation of influenza can be done either by virus culture, RT-PCR or specific neutralizing antibodies in blood. Basic principles of management include prompt institution of infection control measures, early identification of children at higher risk, supportive care and antiviral drugs. Vaccine and chemoprophylaxis are two commonly used methods for prevention of influenza. Currently, inactivated influenza vaccine (IIV) and live attenuated influenza vaccine (LAIV) are available for use with good efficacy. Cough etiquette, use of face masks and hand hygiene are the most important measures to reduce the risk of infection transmission from person to person.

Two years after pandemic influenza A/2009/H1N1: what have we learned?

The world had been anticipating another influenza pandemic since the last one in 1968. The pandemic influenza A H1N1 2009 virus (A/2009/H1N1) finally arrived, causing the first pandemic influenza of the new millennium, which has affected over 214 countries and caused over 18,449 deaths. Because of the persistent threat from the A/H5N1 virus since 1997 and the outbreak of the severe acute respiratory syndrome (SARS) coronavirus in 2003, medical and scientific communities have been more prepared in mindset and infrastructure. This preparedness has allowed for rapid and effective research on the epidemiological, clinical, pathological, immunological, virological, and other basic scientific aspects of the disease, with impacts on its control. A PubMed search using the keywords "pandemic influenza virus H1N1 2009" yielded over 2,500 publications, which markedly exceeded the number published on previous pandemics. Only representative works with relevance to clinical microbiology and infectious diseases are reviewed in this article. A significant increase in the understanding of this virus and the disease within such a short amount of time has allowed for the timely development of diagnostic tests, treatments, and preventive measures. These findings could prove useful for future randomized controlled clinical trials and the epidemiological control of future pandemics.

Epidemiology and clinical presentation of pandemic influenza A (H1N1) among hospitalized children in Kuwait

OBJECTIVE

To describe the epidemiological and clinical characteristics of children hospitalized for the 2009 influenza A H1N1 infection in Kuwait.

MATERIALS AND METHODS

A retrospective chart review of hospitalized children with laboratory-confirmed influenza A H1N1 infection in two hospitals in Kuwait was conducted. Epidemiological characteristics, clinical features, risk factors for severe disease, complications and mortality were analyzed.

RESULTS

The medical records of 197 children hospitalized for the 2009 pandemic H1N1 infection from August 2009 to January 2010 were reviewed. The majority of the children (104; 52.8%) were admitted during the month of October. The median age was 2 years. Most of the admitted children were in two age categories: 64 infants ≤1 year (32%) and 62 schoolchildren >5 years (31%). The most frequent presentations were fever in 193 (98%), cough in 155 (79%) and runny nose in 105 (53%) cases. The majority of the admitted children (109; 55%) had been previously healthy. All children received an antiviral agent (oseltamivir), and antibiotics were administered to 147 (75%). Bacterial co-infections occurred in 3 (1.5%) of all hospitalized children. Six (3%) children were admitted to the intensive care unit, of whom 4 (66%) required artificial ventilation. There was only 1 mortality.

CONCLUSIONS

The pandemic H1N1 infection was associated with a wide spectrum of clinical manifestations. The majority of hospitalized children had previously been healthy. Most of the admitted children had an uncomplicated clinical course.

Clinical and epidemiological characteristics of 2009 pandemic influenza A in hospitalized pediatric patients of the Saurashtra region, India

BACKGROUND

The first case of 2009 pandemic influenza A or H1N1 virus infection in India was reported in May 2009 and in the Saurashtra region in August 2009. We describe the two waves clinicoepidemiological characteristics of children who were hospitalized with 2009 influenza A infection in the Saurashtra region.

METHODS

From September 2009 to February 2011, we treated 117 children infected with 2009 influenza A virus who were admitted in different hospitals in Rajkot city. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) test was used to confirm infection, and the clinico-epidemiological features of the disease were closely monitored.

RESULTS

In the 117 patients, with a median age of 2 years, 59.8% were male. The median time from onset of the disease to influenza A diagnosis was 5 days, and that from onset of the disease to hospitalization was 7 days. The admitted patients took oseltamivir, but only 11.1% of them took it within 2 days after onset of the disease. More than one fourth (29.1%) of the admitted patients died. The most common symptoms of the patients were cough (98.3%), fever (94.0%), sore throat and shortness of breathing. Pneumonia was detected by chest radiography in 80.2% of the patients.

CONCLUSIONS

In children with infection-related illness, the survival rate was about 71% after oseltamivir treatment. The median time for virus detection with real-time RT-PCR is 5 days. Early diagnosis and treatment may reduce the severity of the disease.

Critical findings of severe influenza A (H1N1) pneumonia in children

BACKGROUND

Pandemic influenza A (H1N1) causes severe pneumonia in children. The mechanism of development of respiratory failure in pneumonia patients remains unknown. This report describes clinical features of childhood influenza A pneumonia.

METHODS

The clinical and laboratory findings of 31 H1N1 pneumonia patients hospitalized in Iwata City Hospital from 1 October 2009 to 31 January 2010 were reviewed. Intubation and mechanical ventilation were required due to respiratory failure in eight patients, who were classified as the intubation group. Other patients without mechanical ventilation were classified as the non-intubation group. Clinical features and laboratory findings were compared between the two groups.

RESULTS

The median age was 6.3 years (range, 3-10 years). The male to female ratio was 22:9. Clinical manifestations of tachycardia, tachypnea and cyanosis were significant findings in the intubation group at admission. Lymphocytopenia was observed in both groups. Leukocytosis with neutrophilia was the risk factor for intubation.

CONCLUSIONS

Tachycardia, tachypnea, cyanosis and leukocytosis with neutrophilia, could be useful predictors at admission to identify high-risk influenza A (H1N1) pneumonia in children.

Epidemiological and clinical characteristics of childhood pandemic 2009 H1N1 virus infection: an observational cohort study

Background

There was a pandemic influenza around the world in 2009 including South Korea since last pandemic occurred four decades ago. We aimed to evaluate the epidemiological and clinical characteristics of this infection in childhood.

Methods

We evaluated the epidemiologic characteristics of all the subjects infected with the 2009 H1N1 influenza A virus (2,971 patients, ≤ 15 years of age), and the clinical and laboratory findings of the inpatients (217 patients, 80 had pneumonia) between 1 September 2009 and 31 January 2010 in a single hospital throughout the epidemic.

Results

The age distribution of all the subjects was relatively even. Over 90% of cases occurred during a two-month period. Two hundred and five patients (94.5%) received oseltamivir within 48 h of fever onset, and 97% of inpatients defervesced within 48 h of medication. The group with pneumonia included more males than females, and had higher leukocytes counts with lower lymphocyte differentials than the group without pneumonia. The white blood cell count and lymphocyte differential were associated with the severity of pneumonia. Corticosteroid treatment for severe pneumonia patients was highly effective in preventing disease progression.

Conclusion

Children of all ages affected with even rates of infection, but males were predominant in pneumonia patients. Pneumonia patients showed lymphopenia and its severity was associated with the severity of illness. Our results suggest that the mechanism of lung injury in 2009 H1N1 virus infection may be associated with the host immune response.

H1N1 infection in children with haematological and oncological diseases in Norway

AIM

  To describe the impact of H1N1 infections in children with haematological and oncological diseases during the 2009 H1N1 pandemics.

METHODS

  A short questionnaire was e-mailed to all paediatric departments taking care of patients with oncological and chronic haematological diseases, asking for known cases of H1N1 infections in this patient group.

RESULTS

  Nine children treated for cancer and seven children with haematological diseases were registered. No death occurred, but two patients treated for cancer (acute lymphoblastic leukaemia at diagnosis, acute myeloid leukaemia in chemotherapy-induced bone marrow aplasia) experienced life-threatening respiratory complications.

CONCLUSION

  In all patients with haematological disease and most cases of oncological diseases, the infections ran a mild course. However, life-threatening complications occurred in severely immunosuppressed and neutropenic patients. Delay of anticancer treatment is a concern even in mild cases.

Comparison of pandemic and seasonal influenza in the pediatric emergency department

BACKGROUND

Emergency department (ED) presentation of pediatric pandemic H1N1 (pH1N1) infection is not well characterized. Our objective was to describe the clinical manifestations of pH1N1 in the pediatric ED. We also compared these characteristics to seasonal influenza A, and explored risk factors for pH1N1 hospitalization.

METHODS

We conducted a retrospective cohort study at a pediatric hospital in Quebec City, Canada. Subjects were ED patients aged 0 to 17 years with laboratory-confirmed pH1N1 (April-July 2009) or seasonal influenza A (June 2006-March 2009). Clinical and laboratory data were analyzed by univariate and multivariate log-binomial regression.

RESULTS

A total of 127 pH1N1 cases and 110 seasonal influenza cases were identified. pH1N1 patients were older (9.5 vs. 5.6 years; P < 0.0001) and presented more rapidly (2.8 vs. 3.5 days; P = 0.02). Clinical manifestations were similar, although gastrointestinal findings were less frequent in pH1N1 (relative risk [RR]: 0.49; 95% confidence interval [CI]: 0.37-0.65). Hospitalization risk was similar (RR: 1.12; 95% CI: 0.81-1.55), but hospitalized pH1N1 subjects were more frequently diagnosed with pneumonia (RR: 2.41; 95% CI: 1.16-5.00). In a multivariable model, age <2 years was independently associated with pH1N1 hospitalization (RR: 3.17; 95% CI: 1.78-5.65), whereas the absence of significant comorbidities decreased its risk (RR: 0.51; 95% CI: 0.31-0.85).

CONCLUSIONS

After adjustment for age and delay to presentation, clinical manifestations and 21-day outcomes of pediatric pH1N1 were similar to those of seasonal influenza. pH1N1 patients with previously established risk factors for severe seasonal influenza experienced increased hospitalization risk. Our results suggest that pH1N1 clinical diagnosis and management in the pediatric ED can be performed in a manner similar to seasonal influenza.

Clinical manifestations of influenza caused by A/H1N1v virus among children and teenagers consulted in general practice

BACKGROUND

Children and young adults are more susceptible to pandemic A/H1N1v infection than older people. There are some publications concerning the course of the pandemic influenza among pediatric population but mostly from hospital or from emergency units. There are very few observations of the course of pandemic influenza from primary care settings.

OBJECTIVE

The aim of the study was to describe clinical manifestations of influenza caused by a pandemic strain A/H1N1v among children and teenagers younger than 14 years who were observed, diagnosed, and treated in general practice.

MATERIAL AND METHODS

The observations were conducted among patients with symptoms of an acute respiratory tract infection in an urban area of Warsaw, Poland in November 2009. The inclusion criteria for performing a rapid influenza diagnostic test (RIDT) were established using the CDC definition of 'influenza-like illness' (ILI): fever >38.7°C plus cough and/or sore throat in the absence of another known cause of illness. In patients who met ILI criteria, nasopharyngeal swabs were taken for RIDT and RT-PCR. -

RESULTS

433 patients were consulted by a general practitioner and reported symptoms of an acute respiratory tract infection, 128 (30%) of them met inclusion criteria for ILI and were tested with RIDT: 31 children younger than 14 years and 97 adults. All 31 children suspected of ILI also were tested by RT-PCR. 20 children had a positive result of the rapid influenza test. For all children tested negative, RT-PCR was also negative, and out of 20 children with the presumptive diagnosis of influenza established after rapid influenza test, the diagnosis was confirmed by RT-PCR in 18; their median age was 6.6 years and ranged from13 months to 14 years. The most common symptoms of influenza A/H1N1v were: high fever (>39°C) - 96% of patients, dry cough - 86% of patients, malaise - 78% of patients, headache - 66% of patients, and diarrhea or vomiting - 28% of patients. Two children received treatment with oseltamivir (one boy with congenital heart defect and Down's syndrome and another with severe bronchial asthma). The duration of symptoms ranged from 1 to 13 days (mean of 6.6 days). No patients required hospitalization either due to primary influenza infection or secondary complications.

CONCLUSIONS

The course of influenza caused by virus A/H1N1v in children younger than 14 years observed in a primary care setting was mild and self-limited without the necessity of antiviral treatment in most cases. A rapid influenza diagnostic test is helpful in diagnosing pandemic influenza.

Retrospective analysis of pediatric cancer patients diagnosed with the pandemic H1N1 influenza infection

BACKGROUND

Limited data are available on disease characteristics and outcome of children with cancer who contracted the H1N1 influenza infection during the 2009 pandemic.

METHODS

All 76 pediatric patients with cancer and documented H1N1 infection who presented to the Pediatric Department at King Hussein Cancer Center (KHCC) between October 1 and December 1, 2009 were reviewed for clinical characteristics and course of the disease.

RESULTS

Two-thirds of the patients had hematological malignancies and half were receiving non-intensive chemotherapy at the time of infection. With the exception of two patients who needed pediatric intensive care unit admission, the course of the remaining patients was uneventful whether they were hospitalized or not. No deaths related to H1N1 influenza infection were reported. Sixty-three percent of patients became afebrile within 48 hr of receiving oseltamivir. One-third of hospitalized patients were discharged in < 3 days.

CONCLUSION

The course of H1N1 influenza infection in children with cancer appears to be mild in most cases.

Pediatric hospitalizations associated with 2009 pandemic influenza A (H1N1): an experience from a tertiary care center in north India

OBJECTIVES

To describe our experience in children hospitalized with the pandemic Influenza A (H1N1) from Northern India.

METHODS

The retrospective case study was conducted at the Pediatric ward and Pediatric Intensive Care Unit (PICU) dedicated to the children (aged 18 years or younger) with influenza-like illness (ILI) with positive laboratory test results for pandemic H1N1 by reverse-transcriptase polymerase-chain-reaction assay.

RESULTS

Between August 2009 and January 2010, a total of 100 children were hospitalized with suspected 2009 H1N1 influenza with Category "C" as described by the Government of India. Twenty five patients were positive for H1N1 and 9 for seasonal influenza A. The most common presentation (H1N1 positive) was with fever (100%), cough (100%), coryza (52%), respiratory distress (88%), vomiting (28%) and diarrhea (16%). One child presented with hypernatremic dehydration and seizures (Serum sodium 174 meq/l). Of the H1N1 positive hospitalized children, 7 (28%) had respiratory failure and required PICU admission, 4 (16%) required mechanical ventilation, and 3 (12%) died. The major radiological findings were bilateral pulmonary infiltrates and consolidation. All patients were treated with oral Oseltamivir suspension or capsule as per appropriate weigh band and supportive care as required. Two deaths were caused by refractory hypoxemia and one by refractory shock.

CONCLUSIONS

The exact incidence of Pandemic 2009 H1N1 influenza on morbidity and mortality is difficult to calculate since only Category "C" patients were screened.