|
IAC Express 2009 |
| Issue number 798: May 13, 2009 |
|
|
Please click here to subscribe to IAC Express
as well as other FREE IAC periodicals. |
|
Contents
of this Issue
Select a title to jump to the article. |
- MMWR
Dispatch reports on H1N1 influenza in three pregnant women
|
| |
| Abbreviations |
|
|
AAFP, American Academy of Family Physicians; AAP,
American Academy of Pediatrics; ACIP, Advisory Committee on Immunization
Practices; AMA, American Medical Association; CDC, Centers for Disease
Control and Prevention; FDA, Food and Drug Administration; IAC, Immunization
Action Coalition; MMWR, Morbidity and Mortality Weekly Report; NCIRD,
National Center for Immunization and Respiratory Diseases; NIVS, National
Influenza Vaccine Summit; VIS, Vaccine Information Statement; VPD,
vaccine-preventable disease; WHO, World Health Organization. |
| |
|
Issue 798: May 13, 2009 |
|
|
|
1. |
MMWR Dispatch reports on H1N1 influenza in three pregnant women
On May 12, CDC published "Novel Influenza A
(H1N1) Virus Infections
in Three Pregnant Women--United States, April-May 2009" as an
electronic MMWR Dispatch. The report is reprinted below in its
entirety, excluding references. In addition, you will find links to
pertinent resources at the end of this IAC Express issue.
CDC first identified cases of respiratory infection with a novel
influenza A (H1N1) virus in the United States on April 15 and 17,
2009. During seasonal influenza epidemics and previous pandemics,
pregnant women have been at increased risk for complications
related to influenza infection. In addition, maternal influenza
virus infection and accompanying hyperthermia place fetuses at risk
for complications such as birth defects and preterm birth. As part
of surveillance for infection with the novel influenza A (H1N1)
virus, CDC initiated surveillance for pregnant women who were
infected with the novel virus. As of May 10, a total of 20 cases of
novel influenza A (H1N1) virus infection had been reported among
pregnant women in the United States, including 15 confirmed cases
and five probable cases. Among the 13 women from seven states for
whom data are available, the median age was 26 years (range: 15-39
years); three women were hospitalized, one of whom died. This
report provides preliminary details of three cases of novel
influenza A (H1N1) virus infection in pregnant women. Pregnant
women with confirmed, probable, or suspected novel influenza A
(H1N1) virus infection should receive antiviral treatment for 5
days. Oseltamivir is the preferred treatment for pregnant women,
and the drug regimen should be initiated within 48 hours of symptom
onset, if possible. Pregnant women who are in close contact with a
person with confirmed, probable, or suspected novel influenza A
(H1N1) infection should receive a 10-day course of chemoprophylaxis
with zanamivir or oseltamivir.
Case Reports
Patient A. On April 15, a woman aged 33 years at 35 weeks'
gestation with a 1-day history of myalgias, dry cough, and low-grade fever was examined by her obstetrician-gynecologist. She had
been in relatively good health and had been taking no medications
other than prenatal vitamins, although she had a history of
psoriasis and mild asthma. The patient had not recently traveled to
Mexico. Rapid influenza diagnostic testing performed in the
physician's office was positive.
On April 19, she was examined in a local emergency department, with
worsening shortness of breath, fever, and productive cough. She
experienced severe respiratory distress, with an oxygen saturation
of approximately 80% on room air and a respiratory rate of
approximately 30 breaths per minute. A chest radiograph revealed
bilateral nodular infiltrates. The patient required intubation and
was placed on mechanical ventilation. On April 19, an emergency
cesarean delivery was performed, resulting in a female infant with
Apgar scores of 4 at 1 minute after birth and of 6 at 5 minutes
after birth; the infant is healthy and has been discharged home. On
April 21, the patient developed acute respiratory distress syndrome
(ARDS). The patient began receiving oseltamivir on April 28. She
also received broad-spectrum antibiotics and remained on mechanical
ventilation. The patient died on May 4.
On April 25, a nasopharyngeal swab specimen collected from patient
A indicated an unsubtypable influenza A strain by real-time reverse
transcription-polymerase chain reaction (rRT-PCR) at the San
Antonio Metro Health Laboratory. The specimen was forwarded to the
Virus Surveillance and Diagnostic Branch Laboratory, Influenza
Division, CDC, where testing was inconclusive for novel influenza A
(H1N1) virus. On April 30, a repeat nasopharyngeal specimen was
collected, which was positive by rRT-PCR for novel influenza A
(H1N1) virus at CDC.
Patient B. A previously healthy woman aged 35 years at 32 weeks'
gestation was seen at a local emergency department on April 20 with
a 1-day history of shortness of breath, fever, cough, diarrhea,
headache, myalgias, sore throat, and inspiratory chest pain. She
was febrile (101.6 degrees F [38.7 degrees C]), with a heart rate
of 128 beats per minute, respiratory rate of 22 breaths per minute,
and oxygen saturation of >97% on room air. A chest radiograph was
normal. Rapid influenza diagnostic testing was negative. The
patient received a parenteral nonsteroidal anti-inflammatory
medication, acetaminophen, and inhaled albuterol, and was
discharged home. She was evaluated the following day in her
obstetrician-gynecologist's office, where a nasopharyngeal swab
sample was collected and sent for rRT-PCR testing. The patient
received antibiotics, antinausea medication, acetaminophen, and an
inhaled corticosteroid. The patient recovered fully, and her
pregnancy is proceeding normally.
Patient B had been in Mexico during the 3 days preceding her
arrival at the emergency department. Several family members in
Mexico and the United States had recently been ill with influenza-like illness, and her sister had been hospitalized for pneumonia
during the preceding week. Testing of the nasopharyngeal swab
specimen from patient B collected on April 21 was identified as an
unsubtypable influenza A strain by rRT-PCR testing at the Naval
Health Research Laboratory in San Diego. Additional testing at CDC
confirmed infection with novel influenza A (H1N1) virus.
Patient C. On April 29, a woman aged 29 years at 23 weeks'
gestation was experiencing cough, sore throat, chills, subjective
fever, and weakness of 1 day's duration and was seen at the family
practice clinic where she had been receiving prenatal care. The
patient had a history of asthma but was not taking any asthma
medications. Her son, aged 10 years, reportedly had similar
symptoms the week before the onset of her symptoms. Another son,
aged 7 years, had become ill on the same day as his mother and
accompanied her to the clinic. At the clinic, the younger son was
coughing vigorously and was asked to put on a mask by office staff
members. Rapid influenza diagnostic testing in the family practice
clinic of a nasopharyngeal sample from patient C was positive. The
woman was prescribed oseltamivir, which she began taking later the
same day. Her symptoms are resolving without complications, and her
pregnancy is proceeding normally.
Patient C had not traveled to Mexico recently. Her son aged 7 years
also was prescribed oseltamivir on April 29 but was not tested for
influenza. The physician who evaluated patient C was also pregnant
(13 weeks' gestation). The physician began chemoprophylaxis with
oseltamivir and has remained asymptomatic.
A nasopharyngeal swab collected from patient C on April 29 was
identified as an unsubtypable influenza A strain by the Washington
State Public Health Laboratory. Additional testing at CDC confirmed
infection with novel influenza A (H1N1) virus.
Editorial Note:
This report provides preliminary details on three cases of novel
influenza A (H1N1) virus infection in pregnant women. Additional
information on these cases and other pregnant women with this
infection is being compiled by CDC based on reports from state
health departments. The three pregnant women described in this
report all initially had symptoms of acute febrile respiratory
illness similar to the clinical symptoms in nonpregnant women with
the infection; one patient (patient A) developed ARDS and died. The
most frequently reported symptoms among nonpregnant patients with
novel influenza A (H1N1) virus infection have been fever, cough,
and sore throat.
Although data are insufficient to determine who is at highest risk
for complications of novel influenza A (H1N1) virus infection,
seasonal influenza epidemics and previous influenza pandemics have
shown that pregnant women generally are at higher risk for
influenza-associated morbidity and mortality compared with women
who are not pregnant. The increased risk of complications is
thought to be related to several physiologic changes that occur
during pregnancy, including alterations in the cardiovascular,
respiratory, and immune systems. Pregnant women with underlying
medical conditions such as asthma are at particularly high risk for
influenza-related complications. Because pregnant women are at
increased risk for influenza complications, the Advisory Committee
on Immunization Practices and the American College of Obstetricians
and Gynecologists have recommended that women receive the trivalent
inactivated influenza vaccine.
The novel influenza A (H1N1) virus that is circulating is
susceptible to the neuraminidase inhibitor antiviral medications,
oseltamivir and zanamivir. In randomized, placebo-controlled trials
among outpatients, these medications have reduced the severity and
duration of symptoms of seasonal influenza if started within 48
hours of illness onset, and limited data from observational studies
among hospitalized patients with seasonal influenza indicate that
oseltamivir can reduce mortality, even when started >48 hours after
illness onset. In addition, oseltamivir and zanamivir have been
highly effective in preventing seasonal influenza if used shortly
after exposure to the disease. Little information is available on
the safety or effectiveness of these medications when used during
pregnancy. However, considering the limited information available
and the known risks for influenza complications during pregnancy,
any potential risk to a fetus likely is outweighed by the expected
benefits of influenza antiviral treatment for this novel virus.
Thus, CDC interim guidance indicates that pregnant women with
confirmed, probable, or suspected novel influenza A (H1N1) virus
infection should receive antiviral treatment for 5 days.
Although zanamivir can be used in pregnancy, oseltamivir is
preferred for treatment of pregnant women because of its systemic
absorption. Theoretically, higher systemic absorption might
suppress influenza viral loads more effectively in sites other than
the respiratory system (e.g., placenta) and might provide better
protection against mother-child transmission. Similar to the
recommendation for nonpregnant persons who are treated, oseltamivir
treatment should be initiated as soon as possible, ideally within
48 hours of onset of symptoms. In addition, any pregnant woman
hospitalized with confirmed, probable, or suspected novel influenza
A (H1N1) virus infection should receive oseltamivir, even if >48
hours have elapsed since illness onset. Beginning treatment as
early as possible is critical. In addition, treating fevers in
pregnant women with acetaminophen is important because maternal
hyperthermia has been associated with various adverse fetal and
neonatal outcomes.
In all clinical settings, including settings that provide care for
pregnant women, patients should be screened for signs and symptoms
of febrile respiratory illness at the initial point of contact, and
these patients should be promptly segregated and assessed.
Outpatient clinical settings and labor and delivery units should
develop and implement procedures for handling patients with
respiratory illness and friends or family members who might
accompany them. Pregnant women who are in close contact with a
person who has a confirmed, probable, or suspected case should
receive a 10-day course of chemoprophylaxis with zanamivir or
oseltamivir. For chemoprophylaxis in pregnant patients, a preferred
anti-influenza medication has not been determined. Although
zanamivir might have the benefit of more limited systemic
absorption, respiratory symptoms such as coughing or severe nasal
congestion might limit its usefulness because of its inhaled route
of administration. The pregnant physician caring for patient C
began chemoprophylaxis soon after exposure.
Because of the increased risk for severe complications, the public
health response to outbreaks of novel influenza A (H1N1) virus
should include considerations specific to pregnant women. Interim
guidance on issues specific to pregnant women and the novel
influenza A (H1N1) virus is available at
http://www.cdc.gov/h1n1flu/clinician_pregnant.htm Additional
information regarding novel influenza A (H1N1) virus is available
at http://www.cdc.gov/h1n1flu Clinicians should report cases of
novel influenza A (H1N1) virus infection in pregnant women to their
state or local health departments or CDC.
To access a web-text (HTML) version of the MMWR Dispatch, including
references, go to:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm58d0512a1.htm
To access a ready-to-print (PDF) version of the MMWR Dispatch, go
to: http://www.cdc.gov/mmwr/pdf/wk/mm58d0512.pdf
To receive a FREE electronic subscription to MMWR (which includes
new ACIP recommendations), go to:
http://www.cdc.gov/mmwr/mmwrsubscribe.html
To access CDC's interim guidelines titled "Pregnant Women and Novel
Influenza A (H1N1) Considerations for Clinicians," go to:
http://www.cdc.gov/h1n1flu/clinician_pregnant.htm
To access a transcript of a related CDC press conference of May 12,
go to:
http://www.cdc.gov/media/transcripts/2009/t090512.htm
The home page of CDC's H1N1 Flu web section can be accessed from
http://www.cdc.gov/h1n1flu
IAC has gathered important information related to H1N1 influenza in
a new web section to make it easier to keep up to date with
developments. To access this resource, go to:
http://www.immunize.org/h1n1
Back to top |
| |
|
|
