The index case occurred in a 27-week GA, 965
g of birth weight preterm infant presenting on April 19th
tachypnoea, increase of respiratory secretions and respiratory failure requiring mechanical ventilation. The patient was 79
days old with bronchopulmonary dysplasia. The infant received palivizumab in the same day his rapid test became positive for RSV that means April 19th. At that moment, contact and droplet precaution were initiated. Two weeks apart the onset of RSV infection, the RSV test was still positive.
On 02 May/10 and 03 May/10 two patients in the same NICU of the index case developed respiratory symptoms and tested positive for RSV. Prevention control measures were then implemented and all infants in the same room were tested for RSV, even in the absence of respiratory symptoms. The cases and contacts babies were moved to a semi intensive unit to better cohort them into separate rooms as described below (Figure ). Hand hygiene and environmental cleaning measures were reinforced.
All babies (18 infants) occupying the NICU by the moment of the outbreak were placed in 3 cohorts. Eight of them with negative RSV test were maintained for 7
days in a room under contact precaution considering RSV incubation period. None of these patients developed symptoms during this period and specific precautions were suspended. The remaining 10 infants were positive to RSV and they were placed into two different rooms according to the presence or absence of symptoms. Six presented symptoms and four were asymptomatic. All positive tested patients were isolated in incubators and the use of gloves and mask was oriented to visitors and staff personal.
All RSV positive infants were premature, average GA was 28-weeks (range: 25-34w), birth weight of 1181 grams (range: 560-2575
g) and 50
days old (range: 26–97) at RSV infection diagnosis. Patient characteristics are shown in Table .
Characteristics of the patients in NICU with RSV positive test
Symptomatic infants presented mild to moderate symptoms, with cough, fever and coryza. Two patients (cases 1, 4) and the index case, however, required ventilation support due to RSV infection. Cases 3, 5 and 8 were already under mechanical ventilation and required an increase on ventilatory parameters after the infection. Cases 6, 7, 9 and 10 did not present symptoms. No specific antiviral treatment for RSV infection was given, except palivizumab. In Brazil we do not have inhalatory ribavirin avaible. No death occurred due to RSV infection.
All contacts and the index case received palivizumab. Cases 1, 2, 3 and 9, received palivizumab previously to the onset of outbreak according to institutional policy although cases 1, 2 and 3, presented respiratory symptoms of RSV infection. Palivizumab was prescribed to all other 14 patients occupying the same NICU within the beginning of the outbreak. Palivizumab protection rate for symptomatic infection was 67% (12/18 cases).
RSV positive cases were weekly tested after 14
days of the first detection and, in most cases, still positive at subsequent tests. The longest viral shedding time was 5
weeks. Symptomatic patients were isolated until hospital discharge and the asymptomatic ones were removed from the semi intensive unite when the viral test becomes negative. There were no new cases detected and the outbreak was successfully controlled in 5
days (onset 2 May/10 and last case 6 May/10).