Pandemic 2009 influenza A(H1N1) virus illness among pregnant women in the United States.
BACKGROUND
Early data on pandemic 2009 influenza A(H1N1) suggest pregnant women are at increased risk of hospitalization and death.


OBJECTIVE
To describe the severity of 2009 influenza A(H1N1) illness and the association with early antiviral treatment among pregnant women in the United States.


METHODS
Surveillance of 2009 influenza A(H1N1) in pregnant women reported to the Centers for Disease Control and Prevention (CDC) with symptom onset from April through December 2009.


METHODS
Severity of illness (hospitalizations, intensive care unit [ICU] admissions, and deaths) due to 2009 influenza A(H1N1) among pregnant women, stratified by timing of antiviral treatment and pregnancy trimester at symptom onset.


RESULTS
We received reports on 788 pregnant women in the United States with 2009 influenza A(H1N1) with symptom onset from April through August 2009. Among those, 30 died (5% of all reported 2009 influenza A[H1N1] influenza deaths in this period). Among 509 hospitalized women, 115 (22.6%) were admitted to an ICU. Pregnant women with treatment more than 4 days after symptom onset were more likely to be admitted to an ICU (56.9% vs 9.4%; relative risk [RR], 6.0; 95% confidence interval [CI], 3.5-10.6) than those treated within 2 days after symptom onset. Only 1 death occurred in a patient who received treatment within 2 days of symptom onset. Updating these data with the CDC's continued surveillance of ICU admissions and deaths among pregnant women with symptom onset through December 31, 2009, identified an additional 165 women for a total of 280 women who were admitted to ICUs, 56 of whom died. Among the deaths, 4 occurred in the first trimester (7.1%), 15 in the second (26.8%), and 36 in the third (64.3%);


CONCLUSIONS
Pregnant women had a disproportionately high risk of mortality due to 2009 influenza A(H1N1). Among pregnant women with 2009 influenza A(H1N1) influenza reported to the CDC, early antiviral treatment appeared to be associated with fewer admissions to an ICU and fewer deaths.
Siston
Alicia M
AM
Epidemic Intelligence Service, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Rasmussen
Sonja A
SA
Honein
Margaret A
MA
Fry
Alicia M
AM
Seib
Katherine
K
Callaghan
William M
WM
Louie
Janice
J
Doyle
Timothy J
TJ
Crockett
Molly
M
Lynfield
Ruth
R
Moore
Zack
Z
Wiedeman
Caleb
C
Anand
Madhu
M
Tabony
Laura
L
Nielsen
Carrie F
CF
Waller
Kirsten
K
Page
Shannon
S
Thompson
Jeannie M
JM
Avery
Catherine
C
Springs
Chasisity Brown
CB
Jones
Timothy
T
Williams
Jennifer L
JL
Newsome
Kim
K
Finelli
Lyn
L
Jamieson
Denise J
DJ
D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D004196:Disease Outbreaks; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000188:drug therapy / Q000401:mortality*; D007362:Intensive Care Units; D010343:Patient Admission / Q000706:statistics & numerical data; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy / Q000401:mortality*; D011264:Pregnancy Trimesters; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D000998:Antiviral Agents
J Clin Virol. 2009 Jul;45(3):191-5
19540158
JAMA. 2010 Jan 20;303(3):235-41
20071471
Obstet Gynecol. 2004 Nov;104(5 Pt 1):1125-6
15516422
Vaccine. 2008 Mar 25;26(14):1786-93
18336965
Natl Vital Stat Rep. 2006 Sep 29;55(1):1-101
17051727
Am J Obstet Gynecol. 1959 Dec;78:1172-5
13824729
N Engl J Med. 2009 Nov 12;361(20):1925-34
19815860
Euro Surveill. 2009 Dec 17;14(50):
20070939
N Engl J Med. 2009 Jun 18;360(25):2605-15
19423869
MMWR Morb Mortal Wkly Rep. 2009 May 1;58(16):431-3
19407737
MMWR Recomm Rep. 2009 Aug 28;58(RR-10):1-8
19713882
S Afr Med J. 2009 Oct;99(10):713-4, 716
20128267
Influenza Other Respir Viruses. 2009 Jul;3(4):171-6
19627374
J Clin Virol. 2009 Jul;45(3):205-7
19539521
MMWR Morb Mortal Wkly Rep. 2010 Jan 22;59(2):44-8
20094027
J Antimicrob Chemother. 2003 Jan;51(1):123-9
12493796
N Engl J Med. 2010 Jan 7;362(1):27-35
20032319
MMWR Morb Mortal Wkly Rep. 2009 Sep 25;58(37):1029-32
19779397
CMAJ. 2007 Feb 13;176(4):463-8
17296958
Natl Vital Stat Rep. 2010 Dec;59(3):1-19
25073731
JAMA. 2009 Nov 4;302(17):1872-9
19822627
Clin Infect Dis. 2007 Dec 15;45(12):1568-75
18190317
Clin Infect Dis. 2010 Mar 1;50(5):686-90
20100064
Crit Care Med. 2005 Oct;33(10 Suppl):S390-7
16215363
N Engl J Med. 2009 Aug 13;361(7):728-9
19564634
N Engl J Med. 2009 Nov 12;361(20):1935-44
19815859
Am J Obstet Gynecol. 2009 Dec;201(6):547-52
19850275
CMAJ. 2009 Jul 7;181(1-2):55-8
19528139
MMWR Morb Mortal Wkly Rep. 2009 Aug 7;58(30):826-9
19661856
JAMA. 2000 Feb 23;283(8):1016-24
10697061
Obstet Gynecol. 2010 Apr;115(4):717-726
20308830
Epidemiol Rev. 2006;28:47-53
16731574
MMWR Morb Mortal Wkly Rep. 2005 Mar 4;54(8):196-9
15744227
Am J Public Health Nations Health. 1961 Aug;51:1182-8
13711529
Am J Public Health. 2009 Oct;99 Suppl 2:S248-54
19461110
IMJ Ill Med J. 1976 Dec;150(6):612-6
12100
JAMA. 2009 Nov 4;302(17):1880-7
19822626
MMWR Morb Mortal Wkly Rep. 2009 Apr 24;58(15):400-2
19390508
PLoS One. 2009 Jun 25;4(6):e6051
19557130
MMWR Recomm Rep. 2009 Jul 31;58(RR-8):1-52
19644442
Emerg Infect Dis. 2006 Nov;12(11):1638-43
17283611
BJOG. 2010 Apr;117(5):551-6
20146725
Arch Intern Med. 2003 Jul 28;163(14):1667-72
12885681
BMJ. 2009 Jun 12;338:b2425
19525308
Lancet. 2000 May 27;355(9218):1845-50
10866439
Am J Epidemiol. 1998 Dec 1;148(11):1094-102
9850132
Obstet Gynecol. 2003 Apr;101(4):704-10
12681874
Lancet. 2009 Aug 8;374(9688):451-8
19643469