Severe influenza A(H1N1)pdm09 in pregnant women and neonatal outcomes, State of Sao Paulo, Brazil, 2009

Abstract

To investigate the factors associated with death and describe the gestational outcomes in pregnant women with influenza A(H1N1)pdm09, we conducted a case-control study (deaths and recovered) in hospitalized pregnant women with laboratory-confirmed influenza A(H1N1)pdm09 with severe acute respiratory illness (SARI) in the state of São Paulo from June 9 to December 1, 2009. All cases were evaluated, and four controls that were matched by the epidemiological week of hospitalization of the case were randomly selected for each case. Cases and controls were selected from the National Disease Notification System-SINAN Influenza-web. The hospital records from 126 hospitals were evaluated, and home interviews were conducted using standardized forms. A total of 48 cases and 185 controls were investigated. Having had a previous health visit to a healthcare provider for an influenza episode before hospital admission was a risk factor for death (adjusted OR (ORadj) of 7.93, 95% CI 2.19–28.69). Although not significant in the multiple analysis (ORadj of 2.13, 95% CI 0.91–5.00), the 3rd trimester deserves attention, with an OR = 2.22, 95% CI 1.13–4.37 in the univariate analysis. Antiviral treatment was a protective factor when administered within 48 hours of symptom onset (ORadj = 0.16, 95% CI 0.05–0.50) and from 48 to 72 hours (ORadj = 0.09, 95% CI 0.01–0.87). There was a higher proportion of fetal deaths and preterm births among cases (p = 0.001) and live births with low weight (p = 0.019), compared to control subjects who gave birth during hospitalization. After discharge, control subjects had a favorable neonatal outcome. Early antiviral treatment during the presence of a flu-like illness is an important factor in reducing mortality from influenza in pregnant women and unfavorable neonatal outcomes. It is important to monitor pregnant women, particularly in the 3rd trimester of gestation, with influenza illness for diagnosis and early treatment.

Fatal avian influenza A(H5N1) infection in a 36‐week pregnant woman survived by her newborn in Sóc Trăng Province, Vietnam, 2012

“…Prior studies have indicated that pregnant women are considered a high‐risk population for influenza A(H1N1) pdm09 and avian influenza viruses and are more likely to develop severe complications and to die, especially when infection occurs in the middle and late trimesters . The case‐patient, a 36‐week pregnant woman was exposed to sick chickens and was infected with the avian influenza A(H5N1) virus, developed rapid progressive severe pneumonia, lymphopenia, sever hypoxia and increased aminotransferase levels, similar to previously reported avian influenza A(H5N1) patients Common complications of highly pathogenic avian influenza (HPAI) H5N1 virus infection such as primary pneumonia, respiratory failure due to ARDS, and fatal outcome have been seen and recorded in the case‐patient's clinical progress .…”

“…The case‐patient received an initial presumptive dose of oseltamivir for 5 days after the onset of illness and before influenza infection was confirmed; however, the WHO technical guidelines recommends that patients with suspected influenza should receive oseltamivir as early as possible to reduce mortality . Findings by Riberio et al indicated that antiviral treatment was a protective factor to the A(H5N1) virus when administered within 48 hours of the onset of symptoms.…”

Influenza Virus in Community-Acquired Pneumonia: Current Understanding and Knowledge Gaps

“…24,25 Some evidence showed that early antiviral treatment within 72 hours of disease onset is beneficial. 26 Obesity is another risk factor for severity, hospitalization, and mortality for influenza and BMI is positively associated with the likelihood of hospitalization. [27][28][29] In addition to that, obese patients are more likely to develop secondary bacterial infection.…”

Influenza Virus and Vaccination

“…Infants born to mothers who were vaccinated against influenza may have a decreased rate of preterm birth, low birthweight, and stillborn birth, although establishing a causal relationship is challenging [160,[166][167][168][169][170][171]. Infants born to mothers who were severely sick with H1N1 influenza infection have been shown to have an increased risk of preterm birth, decreased 5 min Apgar scores, and an increased risk of death [172][173][174]. These data support vaccinating pregnant women to help improve the health of both the mother and child.…”