braz j infect dis 2 0 1 8;2 2(3):219–223

The Brazilian Journal of

INFECTIOUS DISEASES
www.elsevier.com/locate/bjid

Original article

Impact of A/H1N1 influenza in children at a

Brazilian University Hospital

Gabriela Fontanella Biondo a,∗ , João Carlos Santana b , Patrícia M. Lago b , Jefferson Piva b ,
Paulo Ricardo A. Souza c , Joana Genz Gaulke c , Juliana M. Sebben d
a Hospital de Clínicas de Porto Alegre (HCPA), Emergência e Medicina Intensiva Pediátrica, Emergência Pediátrica, Porto Alegre, RS, Brazil
b Universidade Federal do Rio Grande do Sul (UFRGS), Departamento de Pediatria, Emergência e Medicina Intensiva Pediátrica (HCPA),
Porto Alegre, RS, Brazil
c Universidade Federal do Rio Grande do Sul (UFRGS), Faculdade de Medicina, Porto Alegre, RS, Brazil
d Hospital de Clínicas de Porto Alegre (HCPA), Residência em Pediatria, Porto Alegre, RS, Brazil

a r t i c l e i n f o a b s t r a c t

Article history: Background: A/H1N1 influenza is a viral disease that affects a significant part of the
Received 13 December 2017 population mainly in winter, leading to increased number of medical consultations, hos-
Accepted 13 May 2018 pitalizations and consequently care spending in emergency.
Available online 5 June 2018 Methods: This is a case-series retrospective study, involving patients admitted to a tertiary
hospital in southern Brazil in 2016 with a clinical diagnosis of acute respiratory infection of
Keywords: the influenza type and laboratory confirmation of influenza A/H1N1.
H1N1 influenza Results: 64 patients were included, mostly male, median age of 48.3 months. Chronic under-
Emergency lying diseases were found in 73% of the patients, and these patients evolved to the most
Critical care unfavorable outcome. About vaccination, of the 57 patients with an age range for vaccina-
Children tion, only 28% had complete vaccination coverage. The main clinical manifestations found
in the included patients were fever, cough, intercostal indrawing, wheezing, tachypnea and
pulmonary crackles. These patients were mainly followed-up with laboratory tests and chest
X-ray. Consolidation was evident in 43% of patients followed by interstitial infiltrate in 33%. A
five-day course of neuraminidase inhibitor was prescribed for all patients, as recommended
by the WHO, but due to the complications, 73% of the patients required antibiotic therapy,
and 61% oxygen therapy. The majority of patients had a favorable outcome, but 11 required
intensive care and one died.
Conclusions: A/H1N1 influenza persists as an important public health problem, mainly due
to high morbidity and hospitalization rates. It is important to identify patients with A/H1N1
influenza and clinical situations with higher risk of complications. Through this study, it
is possible to analyze the characteristics of pediatric patients with A/H1N1 influenza and
mainly to emphasize assistance of populations with comorbidities, since they present higher
rates of complications and death.
© 2018 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. This is an
open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/
by-nc-nd/4.0/).

∗
Corresponding author.
https://doi.org/10.1016/j.bjid.2018.05.004
1413-8670/© 2018 Sociedade Brasileira de Infectologia. Published by Elsevier Editora Ltda. This is an open access article under the CC
BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
220 b r a z j i n f e c t d i s . 2 0 1 8;2 2(3):219–223

50
Introduction 45
40 38
Influenza A/H1N1 is an acute infectious disease with great 35
morbidity, capable of impacting the routine of individuals, 30
such as absenteeism at school and at work, increasing the 25 23
number of visits to medical care units, resulting in higher cost 20
15
of care and overcrowding hospitals. In children, the outcome
10
of the disease tends to be less favorable. In addition, children
5
are important vectors for spreading the disease.1–4 1 1
0 1
In Brazil, in 2016, even before the winter months, sev-

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eral cases of A/H1N1 influenza were diagnosed, specially in

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the adult population. The legacy of the 2009 pandemic was
essential for the establishment of diagnostic protocols and Fig. 1 – Monthly distribution of pediatric patients with
clinical management, avoiding panic amongst the populations A/H1N1 influenza at HCPA in 2016.
involved.
The objective of this study was to analyze a case-series of
pediatric patients admitted to Hospital de Clínicas de Porto
Table 1 – Underlying chronic diseases in pediatric
Alegre (HCPA) in 2016 with A/H1N1 influenza, taking into patients with A/H1N1 influenza at HCPA in 2016.
account demographic characteristics, risk factors, clinical and
Comorbidity n %
laboratory manifestations, length of hospitalization, therapy
a
used, and disease outcome. Chronic pneumopathies 25 39
Neurological disease 6 25
Solid tumor, leukemia 9 14
Metabolic, genetic or hepatic disease 7 11
Congenital heart disease 4 6
Methods Chronic Nephropathy 1 1.5
Absence of comorbidity 17 27
HCPA is a public teaching hospital of the Federal University a
Asthma, cystic fibrosis, obliterans bronchiolitis.
of Rio Grande do Sul (UFRGS), Brazil. It is an 842-bed tertiary
care facility with an average of 30,000 admissions/year. Dur-
This study was approved by the Research Ethics Com-
ing 2016 all pediatric patients admitted to HCPA with a clinical
mittee of the HCPA, under the registration number CAAE
diagnosis of influenza-like acute respiratory infection with
62915716.5.0000.532.
laboratory confirmation of influenza A/H1N1 virus by RT-PCR
(polymerase chain reaction) collected from the nasopharynx
were included in the study.1,5,6 This was a case-series retro- Results
spective study with data abstracted from patients’ records.
The eligibility criteria were: (a) age between 1 month and The study included 64 pediatric patients with diagnosis of
14 years; (b) clinical diagnosis of A influenza according to A/H1N1 influenza confirmed by RT-PCR. The majority of these
criteria of the World Health Organization (WHO), Centers for patients were male (66%) and residing Porto Alegre (58%). The
Disease Control and Prevention (CDC), and the Brazilian Min- median age was 48.3 months, 20 (31%) were less than one
istry of Health: “fever with sudden onset, even if reported, year old. The monthly distribution of these patients may be
accompanied by cough or sore throat and at least one of these observed in Fig. 1.
symptoms – myalgia, headache or arthralgia. In children less Out of the 64 included patients, 42 (66%) had their diag-
than two years of age, with no other specific diagnosis: sud- nosis performed at the Pediatric Emergency Unit (PEU), 17
den onset of fever, even if reported, and respiratory symptoms (27%) at the Pediatric Inpatient Unit (PIU), three (5%) at the
– cough, coryza and nasal obstruction; and (c) laboratory con- Pediatric Intensive Care Unit (PICU) and two (3%) at Pediatric
firmation of A/H1N1 influenza by RT-PCR in a sample collected Oncology Unit (POU). Of those, 47 (73%) patients had one or
with a nasopharyngeal swab”.1,5,6 more pre-existing chronic underlying disease, including pneu-
Personal and family history, demographical, epidemiolog- mopathies (asthma, cystic fibrosis, obliterans bronchiolitis),
ical, clinical and laboratory data, and disease outcome of neuropathies, immunosuppression, or metabolic and genetic
included patients were recorded and stored in a database. diseases, as seen in Table 1. Several patients had an associa-
Continuous variables are expressed in absolute values and tion of two or more chronic conditions.
percentages, together with mean, median, and standard devi- Overall, seven (11%) individuals were less than six months
ation. Pearson’s chi-square test was used to compare the of age, therefore within an age group with no indication for
categorical variables or Fisher’s exact test for variables with influenza A vaccination. Of the remaining 57 patients, only 16
expected values lower than 5. Variables with non-normal dis- (28%) had been vaccinated.
tribution were compared with the Mann–Whitney test. The The main clinical manifestations were fever (83%), cough
value of p < 0.05 was considered statistically significant. IBM (73%), intercostal indrawing (52%), wheezing (41%), tachypnea
Statistical Package for the Social Sciences (IBM SPSS Statistics (39%) and pulmonary stertor crackles (39%). No gastroin-
17.0) was used for all statistical analyses. testinal manifestations were present in the initial clinical
 b r a z j i n f e c t d i s . 2 0 1 8;2 2(3):219–223 221

Table 2 – Clinical manifestations in pediatric patients with A/H1N1 influenza in HCPA at 2016 according to disease
progression and age group (n = 64).
Day Tachypnea Intercostal indrawing Fever

<1 yr >1 yr p <1 yr >1 yr p <1 yr >1 yr p

n = 20 n = 44 n = 20 n = 44 n = 20 n = 44
n (%) n (%) n (%) n (%) n (%) n (%)

Day 1 10 (50) 15 (34) 0.27 15 (75) 18 (41) 0.15 14 (70) 39 (88) 0.08
Day 2 10 (50) 17 (39) 0.42 15 (75) 18 (41) 0.15 8 (40) 23 (52) 0.42
Day 3 4 (20) 12 (27) 0.75 13 (65) 10 (23) 0.02 5 (25) 21 (48) 0.10
Day 4 2 (10) 9 (20) 0.47 11 (55) 9 (20) 0.009 4 (20) 17 (39) 0.16
Day 5 2 (10) 5 (11) 1.00 7 (38) 6 (14) 0.009 2 (10) 13 (29) 0.07

examination of these patients. Most of the signs and symp- influenza in pediatric patients were diagnosed at the end
toms became less frequent from the third day on, regardless of of March and the main hospitalization period was between
the patient’s age. Particularly, it should be noted that the pres- April and May, months before winter. Similarly, anticipation
ence of intercostal indrawing was more significant in children of positive cases of A/H1N1 influenza was seen in February.
less than one year old also from the third day of hospitaliza- Although A influenza occurs during the whole year, it is mainly
tion (65% vs. 23%, p < 0.05), according to Table 2. The mean prevalent in the cold months.7,8,10 When the first cases arises,
interval between onset of symptoms suggestive of influenza A influenza spreads rapidly. Considering the pediatric pop-
A and collection of respiratory secretion for viral PCR was 1.6 ulation, the incubation period of the influenza virus varies
days. from one to four days and the transmissibility lasts, on aver-
Overall, 96 chest radiographs and 68 hemograms (blood age, for 10 days, but can be prolonged in immunosuppressed
count) and biochemical studies were requested. At hospi- patients.7–16
tal admission, pulmonary radiographs were requested for 52 In the current study, the majority of cases were male
(81.2%) patients. The main radiological findings on this first residing in Porto Alegre metropolitan area with similar demo-
day of hospitalization were pulmonary consolidation in 27 graphic characteristics of other groups surveyed.1,8,11 Patients
(43%), interstitial infiltrate in 21 (33%), or normal pattern in with A/H1N1 influenza and underlying chronic illnesses,
12 (19%). besides having a potential for increased transmissibility of
All patients were orally treated with neuraminidase the disease, are also thought to have greater morbidity, espe-
inhibitor (oseltamivir) for five days, as recommended by the cially severe pneumonia, and mortality. In this study, 73% of
WHO and the Ministry of Health. A total of 47 patients received the patients presented some comorbidity. Studies of pediatric
antibiotic therapy (73%), but only 10 (16% of the total) started patients with A/H1N1 influenza in 2009 reported about one-
that treatment on the first day of hospitalization. Oxygen ther- third (32 and 35%) of pre-existing clinical conditions, including
apy was required in 39 (61%) patients. asthma, immunosuppression, chronic lung disease, and neu-
Regarding clinical evolution, of the 42 patients diagnosed rological disorder.1,7,11,17,18
with influenza A/H1N1 in the Pediatric Emergency Unit (PEU), Worldwide, vaccination against A/H1N1 influenza is rec-
17 (27% of the total) were discharged after a mean hospital stay ommended for all infants between six and 24 months,
of 1.1 days. On the other hand, 24 patients were transferred to including those previously healthy, to provide protection
Pediatric Admission Unit (PAU) and had a mean hospital stay against clinical complications of the disease, and to reduce
of 9.5 days (p < 0.05). All the 17 (27%) patients who had the diag- the spread of the virus, morbidity and mortality, including in
nosis of A/H1N1 influenza performed at PAU were discharged elderly groups. Even so, vaccination coverage remains very low
after average hospital stay of 11.6 days. Of all the patients stud- in several countries.2,3,8,11,19–22 Vaccination coverage against
ied, 11 (17%) needed PICU care, two of whom were transferred A/H1N1 influenza in the present study was of only 28%.
from another hospital. They all had an underlying chronic ill- The main clinical manifestations of patients with A/H1N1
ness. Only one (2%) patient died (with chronic liver disease). influenza in this study were fever, cough, intercostal indraw-
Patients with A/H1N1 flu tied up a total of 506 hospital bed- ing, wheezing, tachypnea and pulmonary crackling stertors.
days. Those clinical signs decreased in frequency after the third day
of disease progression. As the observed clinical manifesta-
tions of mild cases are very similar to those seen in seasonal
Discussion influenza and in other viral respiratory diseases, the diagnos-
tic delay is common. The most serious situations, however, are
In April 2009, the CDC identified pandemic influenza A/H1N1 accompanied by fever, cough, shortness of breath, fatigue or
(2009) virus and in July, WHO declared a new pandemic caused weakness, chills, myalgia, rhinorrhea, sore throat, headache,
by this viral subtype. Worldwide, during the pandemic phase, wheezing, vomiting, and diarrhea. The present study did not
the finding of sustained transmission of this virus resulted find a relationship between symptoms and age group, but
in changes in the investigation and management of cases highlighted the significantly greater presence of pulmonary
of influenza-like illness. In the following years the circula- stertors in children less than one year of age, especially after
tion of A/H1N1 virus continued to be observed along with the third day of hospitalization. Some studies highlight the
other seasonal viruses.7–9 In 2016, at HCPA, cases of A/H1N1 importance of gastrointestinal symptoms, especially in the
222 b r a z j i n f e c t d i s . 2 0 1 8;2 2(3):219–223

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