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Viral respiratory disease in pregnancy Ryan E. Longman and Timothy R.B. Johnson Purpose of review Recently there has been an increased concern over viral respiratory infections and their potential for a pandemic. This concern makes it important to review the most current guidelines for the management of viral respiratory diseases in pregnancy. Recent findings The topics covered are influenza, avian influenza, and severe acute respiratory syndrome. Summary Pregnant women have an increased susceptibility to viral respiratory diseases. The most common respiratory virus to infect pregnant women is influenza. All women who intend to become pregnant or are pregnant should receive the influenza vaccine. If a pregnant woman develops influenza she should be treated with supportive care. Antiviral medications should be reserved for cases where the benefits outweigh the risks. Avian influenza (H5N1) is a new emerging virus usually contracted from direct contact with diseased birds. There is no commercially available vaccine at this time to prevent infection. Pregnant women should be treated aggressively with supportive care and antiviral medications, as the significant risk of maternal mortality outweighs the potential fetal risks. Pregnant women diagnosed clinically with severe acute respiratory syndrome should be treated empirically, as a serologic diagnosis can take weeks to confirm. The treatment of pregnant women with severe acute respiratory syndrome should be without ribavirin. Keywords avian influenza, influenza, severe acute respiratory syndrome Curr Opin Obstet Gynecol 19:120–125. ß 2007 Lippincott Williams & Wilkins. Obstetrics and Gynecology, University of Michigan, Women’s Hospital, Ann Arbor, Michigan, USA Correspondence to Dr Timothy R.B. Johnson, MD, Bates Professor and Chair, Obstetrics and Gynecology, University of Michigan, Women’s Hospital, 1500 East Medical Center Drive, Room L4000, Ann Arbor, MI 48109-0276, USA Tel: +1 734 763 0983; fax: +1 734 763 5992; e-mail: [email protected] Current Opinion in Obstetrics and Gynecology 2007, 18:120–125 Abbreviations ACOG CDC PCR SARS American College of Obstetricians and Gynecologists Center for Disease Control polymerase chain reaction severe acute respiratory syndrome ß 2007 Lippincott Williams & Wilkins 1040-872X Introduction Pregnancy significantly alters maternal respiratory physiology. The rise in progesterone levels stimulates the brain’s respiratory center, creating a functional state of hyperventilation, while the enlarging gravid uterus alters lung volumes and creates the maternal perception of dyspnea. In addition, pregnancy has also been noted to affect the immune system by decreasing the cytotoxic lymphocytic activity. All of these physiologic changes that take place are intended to help the pregnant patient successfully adapt to gestation, but they can also be detrimental to maternal well-being. One of the deleterious effects caused by these adaptations in pregnant patients is the diminished ability to compensate for and resist viral respiratory infections. The most common respiratory virus that takes advantage of this susceptibility is influenza. In addition, there has recently been increased concern over new antigenic strains of influenza and other classes of viruses that result in aggressive virulent respiratory disease. The purpose of the present article is to review these viral respiratory diseases in the gravid patient and to address recent updates in management. Influenza Influenza is an acute respiratory disease that affects an estimated four million people per year. The three isotypes of the influenza virus that cause disease are influenza A, influenza B, and influenza C. Influenza A is the most common and the most virulent [1,2]. The virus is spread through aerosolized respiratory droplets followed by disease onset 1–4 days after exposure. The symptoms with which patients present are fever, cough, headache, malaise, nausea, vomiting, rhinorrhea, and myalgia. The viral illness usually resolves after 5 days [1,3]. Influenza prevention consists of a yearly vaccine. There are two types of vaccines commercially available: an inactivated vaccine that is delivered intramuscularly, and a live attenuated vaccine that is delivered intranasal. Vaccines developed for use in the United States aim to immunize against three antigenic strains of influenza per year – two subtypes of influenza A, and influenza B. The annual selection of viruses included in the vaccine depends upon the occurrence of new subtypes of influenza causing outbreaks in other parts of the world. Current vaccines provide protection against the virus with an efficacy of 70–100% in healthy adults. Severe adverse reactions are rare [4]. 120 Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Viral respiratory disease in pregnancy Longman and Johnson 121 If the patient did not receive the vaccine and symptoms of influenza have already appeared, then treatment consists of supportive care with or without antiviral medications. There are two groups of antiviral medications used in the treatment of influenza: ion channel blockers and neuraminidase inhibitors. Amantadine and rimantadine are both ion channel blockers. These blockers act by blocking the influx of hydrogen ions into endocytosed vesicles that contain virus particles. By inhibiting the influx of hydrogen ions they prevent a drop in vesicle pH. Without this decrease in pH, the virus is not able to activate its replication pathway. Both amantadine and rimantadine are 50% effective in preventing infection and 70–90% effective in preventing illness in exposed individuals. When given to patients with acute influenza illness, within the first 48 h of symptoms, they have been shown to decrease the time to recovery by 1 day [4]. The two neuraminidase inhibitors used in the treatment of influenza are zanamivir and oseltamivir. They act to decrease the activity of neuraminidase, which prevents the influenza virus from entering and being released from cells. Zanamivir and oseltamivir should be started within the first 2 days of the influenza illness and have been shown effective in reducing the duration of symptoms by 24–36 h [4]. Amantadine and rimantadine are approved for the prophylaxis and treatment of influenza A, while zanamivir and oseltamivir are approved for treatment only of influenza A and influenza B. Treatment with these medications should last for 5 days and for no longer than 2 weeks to prevent drug resistance [4]. Pregnant women have an increased rate of morbidity and mortality from influenza infection. The increased risk of influenza for the pregnant patient was first reported after the epidemic of 1918 when mortality was noted to be as high as 49% [5,6], and was further noted during the epidemic of 1957 when 50% of reproductive age women that died were pregnant [7–9]. Later studies better qualified the risk of influenza for the pregnant patient to the third trimester when the risk of hospitalization for an acute cardiopulmonary illness is three to four times more likely than for a nonpregnant or postpartum woman [10–12]. The influenza virus can cross the placenta [13] but does not increase the risk of a preterm delivery or a low-birthweight infant [11,14]. The effect of fetal viremia on congenital anomalies and psychiatric disorders is contested [3,15,16]. Management of influenza in pregnant patients consists of prevention and supportive care. Prevention consists of providing pregnant women with the yearly influenza vaccine. The American College of Obstetricians and Gynecologists (ACOG), along with the Center for Disease Control (CDC), recommend that all women that are or intend to become pregnant during the influenza season should be vaccinated. A new recommendation in the ACOG committee opinion from 2004 [17] is that pregnant patients can be vaccinated in all three trimesters. ACOG also reminds practitioners that it is the inactivated intramuscular vaccine that should be used during pregnancy and not the attenuated intranasal vaccine [17]. Even though significant evidence continues to show the efficacy [18,19] and safety [20,21] of the influenza vaccine, only a small percentage of pregnant patients actually receive it [22–24]. To better identify reasons for the low vaccination rate in pregnant women, the ACOG and the CDC surveyed a national sample of obstetricians. They found that while 95% would recommend the vaccine in the second and third trimesters, only 52% would suggest it during the first trimester. Of those physicians that would recommend the vaccine, 36–38% did not provide the vaccine at their practice. Based on these findings the ACOG and the CDC made two recommendations: first, educate providers to recommend the vaccine in the first trimester; and, second, increase the availability and access of the vaccine to patients [25]. The use of antipyretics should be stressed for the treatment of fever as not only does it reduce fetal tachycardia, but it has also been associated as a protective agent against congenital abnormalities [3]. Some authors have suggested elective delivery in pregnant women if their respiratory status becomes compromised, but there is no definitive evidence to support this form of management [26]. Delivery should be reserved for obstetrical indications. The use of antiviral medications in pregnancy is controversial. There are only very limited animal studies and human cases were these medications have been administered to pregnant women [27–33]. The most studied of all the antiviral medications in pregnancy is amantadine. Animal studies of the drug have yielded conflicting results. Vernier et al. [28] treated both rabbits and rats with amantadine at doses as high as 32 mg/kg and found no evidence of teritogenic events. Lamar et al. [29] also treated rabbits and rats with amantadine but at doses of up to 100 mg/kg. The rabbits treated with amantadine showed no evidence of teratogenic malformations or fetal resorptions, while the rats were noted to have increased rates of teritogenic malformations and fetal resorptions at doses of 50 mg/kg, 12 times the human dose [29]. The human studies in which amantadine was administered to pregnant patients consist of two case reports and two small case series. One of the case reports found pregnant women exposed to amantadine in the first trimester of pregnancy produced fetuses with cardiac anomalies, Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 122 Maternal-fetal medicine while the second case report and the two case series failed to identify any increased risk of teratogenisis [30–33]. There are no animal or human reports in the English literature on the effects of rimantadine, zanamivir, or oseltamivir on gestation [27]. Even though no conclusive data have shown antiviral medication to be harmful or teratogenic, the ACOG recommends that use of the medication be limited only to cases where the potential benefits outweigh the potential risks [17]. The best way to prevent infection with avian influenza is to avoid travel to infected regions. If travel to an infected area is necessary, then direct contact with poultry and their feces should be avoided. When consuming eggs or other poultry products, they must be thoroughly cooked [40]. Unfortunately, there are no commercially available vaccines for the H5N1 virus and the seasonal influenza vaccine does not provide protection against avian influenza strains [41,42,43,44,45]. Avian influenza Treatment for avian influenza consists of supportive care and an antiviral medication, oseltamivir. There is limited evidence that oseltamivir can reduce viral replication and improve survival. To be effective, oseltamivir should be administered within 48 h of the onset of symptoms, but since the illness has such a high mortality rate it is suggested that the medication be started even if the patient is outside the 48 h time period [34,35]. Recently there has been increasing concern over the emergence of new antigenic influenza strains. The strain that appears to raise most concern is a type A avian influenza, H5N1. Wild birds are known to harbor the avian influenza virus in their intestines and act as the natural reservoir for the disease. While the wild birds remain asymptomatic they can infect other bird species, such as poultry, which can develop a symptomatic illness. There are several subtypes of avian influenza and they usually produce an illness that manifests itself as a mild effect on the respiratory system or reduction in egg production. Occasionally, infection can occur with a more pathogenic strain that can cause severe disease with a mortality rate of almost 100%. The viral strains that cause the severe form of the disease are the H5 and H7 subtypes [34,35]. The risk of human infection with avian influenza is low because the strains only rarely cross species from birds to people. Of the several subtypes of avian influenza, only four strains are known to have infected humans: H5N1, H7N3, H7N7, and H9N2. With the exception of the H5N1 strain, which is extremely pathogenic, these viral strains only produce mild disease [34,35]. The first set of confirmed human cases of H5N1 influenza was in 1997 in Hong Kong, where 18 individuals were diagnosed with the virus [34,36,37]. Two additional outbreaks have occurred since then. Transmission appears to occur from direct contact with infected poultry or their feces [34,35]. Only very rare occurrences of person-to-person transmission have been reported [38]. The clinical course of H5N1 in humans can be aggressive with rapid deterioration. After an incubation period of 2–8 days, patients present with a high fever and typical influenza-like symptoms. Patients tend to rapidly deteriorate over the next 1–2 weeks, developing pneumonia, respiratory distress, and multiorgan failure. Approximately 50% of the cases are fatal [34,35]. The clinical diagnosis of H5N1 influenza can be confirmed with the detection of H5-specific RNA or by viral isolation [39]. There is only one reported case in the literature of a pregnant woman with avian influenza. The case occurred in a 4-month pregnant woman in the Anhui Province of China. The patient became ill approximately 7 days after participating in the slaughtering and defeathering of sick poultry that was being prepared for consumption by her family. Five days after becoming acutely ill she presented to the hospital with increasing fever, dyspnea, tachycardia, and tachypnea. The patient’s chest radiograph showed diffuse bilateral infiltrates. The woman was admitted to hospital and started on antibiotics. That night her respiratory status deteriorated and she required intubation with mechanical ventilation. The next day the patient’s chest radiograph showed increased diffuse infiltration. The patient developed disseminated intravascular coagulation along with multiorgan failure and died 3 days after hospital admission. A definitive diagnosis of avian influenza was made by identifying H5N1 genes from tracheal aspirates using polymerase chain reaction (PCR) and was confirmed with complete sequencing of the viral genome [46]. Even though this is only one case, it demonstrates the potential rapid and aggressive course of avian influenza in pregnant patients. Pregnant women with suspected avian influenza should be treated early and aggressively with supportive care and oseltamivir. The possible benefits of oseltamivir, an antiviral medication, would certainly outweigh the fetal risks, given the high potential for maternal mortality. Severe acute respiratory syndrome Severe acute respiratory syndrome (SARS) is a novel coronavirus that first appeared as a worldwide cause of respiratory disease in 2003 [47,48]. The virus was felt to originate in the Guangdong Province in Southern China. It is suspected that the novel coronavirus originated when Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Viral respiratory disease in pregnancy Longman and Johnson 123 it jumped species from the civet cat to humans. The index case that led to the worldwide spread of the virus is that of a 64-year-old physician from southern China that traveled to Hong Kong and infected multiple other individuals in his hotel, which resulted in a subsequent spread of the outbreak to Hong Kong, Vietnam, Singapore, and Canada [49–54,55]. The clinical course of patients with SARS follows a triphasic pattern. The first phase is characterized by viral replication that presents with fever, myalgia, and constitutional symptoms. These symptoms are usually transient and resolve after a few days. Phase two, which is characterized as the immune pathologic stage, presents with recurrence of fever, oxygen desaturation, and radiological progression of pneumonia while the viral load falls. Most patients usually respond to treatment by the end of the second stage, but approximately 20% will proceed to phase three, which is characterized by acute respiratory distress syndrome requiring ventilator support [50,55, 56,57]. The diagnosis of SARS is initially based on clinical presentation. Patients that are given a clinical diagnosis of SARS are then further categorized into two groups. The first group is made up of patients with suspected SARS, which consists of people that present with fever, cough, and a history of close contact with a SARS patient, people that travel to a SARS-infected region, or people that live in a SARS-infected region. A recently deceased patient who died with an unexplained respiratory illness without an autopsy and who had a history of recent contact with a SARS patient, lived in a SARS endemic region, or recently traveled to a SARS-infected region should also be categorized as a suspected SARS case. The second group of patients is categorized as probable SARS cases. A probable case of SARS is a suspected case that also has chest radiographic evidence of infiltrates consistent with pneumonia or respiratory distress syndrome, positive laboratory testing, or autopsy findings consistent with respiratory distress syndrome and no identifiable cause [58,59]. Patients with either a suspected case or a probable case of SARS are both treated empirically. The distinction of suspected versus probable is only for the use of reporting cases. The CDC [58] requires suspected and probable cases to be reported, while the World Health Organization [59] only requires the reporting of probable cases. A definitive diagnosis of SARS is made through laboratory testing. There are three types of tests used to confirm the diagnosis. The first is serologic testing for SARS virus antibodies by means of enzyme-linked immunosorbent assay or indirect fluorescent antibody testing. For the serologic test to be positive there must be a four-fold or greater rise in the antibody titer between the acute and convalescent stages, or the documentation of a negative antibody test in the acute stage followed by conversion to a positive test in the convalescent stage. The difficulty with serologic testing is that SARS patients can take up to 21 days to seroconvert, making it a difficult tool to use to obtain a negative diagnosis. The second method of testing is reverse transcriptase-PCR to identify RNA from the SARS coronavirus. RNA must be isolated from at least two different specimens or from the same specimen collected on two different days of the illness. The third method is isolation of the virus by cell culture with reverse transcriptase-PCR confirmation [58,60]. Once a clinical diagnosis of SARS is made, patients are treated empirically while waiting for laboratory test results to make the definitive diagnosis. Treatment consists of methylprednisone, ribavirin, levofloxacin, and ventilation if the oxygen saturation drops to below 96% while on 6 l/min oxygen [61]. Only 15 cases of SARS have been reported in pregnant patients since 2002 [51,52,62,63,64]. Even though the case numbers of pregnant women with SARS is limited, there appears to be a 25% mortality associated with SARS in pregnancy [62], which is significantly higher than the general population mortality of 9.6% [49]. Wong et al. [62] performed a multicenter observational study of 12 pregnant women with a diagnosis of probable SARS. All 12 patients were treated with broad-spectrum antibiotics, ribavirin, and hydrocortisone while their diagnosis was confirmed with antibody testing or reverse transcriptase-PCR. Wong et al. found an overall rate of intensive care unit admission of 50%, a rate for mechanical ventilation of 33%, and a rate for maternal death of 25%. Of the seven patients with a first-trimester pregnancy, 57% had spontaneous abortions. Of the five women diagnosed with SARS in the second and third trimesters, 80% had preterm deliveries and 40% had intrauterine growth restriction. None of the newborns showed evidence of seroconversion [62]. In another study by Lam et al. [63] that looked at the same 12 pregnant women but in a comparison with 40 matched nonpregnant SARS patients, the authors found that the pregnant women had longer hospital stays along with increased risks of renal failure, sepsis, disseminated intravascular coagulation, intensive care unit admissions, and death. Not all reports in the literature show such a poor prognosis for pregnant patients with SARS. There are three case reports of pregnant women with SARS that were treated in North America (two in the United States and one in Canada). The two cases in the United States were of pregnant patients in their first and second trimesters, while the Canadian patient was in her third trimester. Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. 124 Maternal-fetal medicine The three patients were treated with broad-spectrum antibiotics and steroids, without ribavirin. All three women recovered and delivered healthy newborns [51,52,64]. One of the main differences between these cases and the series from Hong Kong was the use of ribavirin. The suggested treatment of pregnant women with SARS is similar to that of their nonpregnant counterparts with two exceptions – pregnant women should receive clarithromycin and amoxicillin/clavulanic acid instead of levofloxacin [61], and ribavirin should be avoided, especially in the first trimester. Ribavirin is a known teratogen in animals and has not been tested in humans [65,66]. In addition, there is no proof that ribavirin hastens the recovery from SARS [58,64]. Pregnant women with mild or controlled disease do not require elective delivery. The suggested criteria for early delivery are rapid maternal deterioration, failure to maintain adequate oxygenation, multiorgan failure, fetal compromise, and difficulty with ventilation secondary to a gravid uterus [67]. Newborns delivered by women with either acute or convalescent SARS do not appear to be at risk of vertical transmission, but since antibodies to SARS have been found in the breast milk, patients are advised against breast feeding until more is known about transmission [51,52,62,63,64,67,68]. Conclusion Viral infection plays an important role in respiratory diseases of pregnant women. The most common viral respiratory infection in pregnant women is influenza. All women that are pregnant or intend to become pregnant should receive the influenza vaccine. Women that did not receive the vaccine and develop an acute case of influenza should be treated symptomatically, including the use of antipyretics. Pregnant women should only be treated with antiviral medications when the benefits outweigh the risks. A new emerging antigenic strain of influenza is H5N1. The virus is usually contracted through direct contact with infected birds. There is no commercially available vaccine at this time to prevent H5N1 infection. Pregnant women should be treated aggressively with supportive care and antiviral medication, as the significant risk of maternal mortality outweighs the potential fetal risks. SARS is a novel coronavirus that can cause severe respiratory disease with a significant level of mortality in pregnant women. Pregnant women diagnosed clinically with SARS should be treated empirically, as a serologic diagnosis can take weeks to confirm. The treatment of pregnant women with SARS should be without the use of ribavirin. References and recommended reading Papers of particular interest, published within the annual period of review, have been highlighted as: of special interest of outstanding interest Additional references related to this topic can also be found in the Current World Literature section in this issue (p. 198). 1 Whitty JE, Dombrowski MP. Respiratory diseases in pregnancy. In: Creasy RK, Resnik R, Iams JD, editors. Maternal–fetal medicine: principles and practice, 5th ed. Philadelphia, PA: Saunders; 2004. pp. 953–974. 2 Goodnight WH, Soper DE. Pneumonia in pregnancy. Crit Care Med 2005; 33:S390–S397. A concise overview of the management of pneumonia in pregnancy. Acs N, Banhidy F, Puho E, Czeizel AE. Maternal influenza during pregnancy and risk of congenital abnormalities in offspring. Clin Mol Teratol 2005; 73:989–996. A retrospective data review that demonstrates the importance of antifever drugs in pregnant women with influenza. 3 4 Couch RB. Prevention and treatment of influenza. N Engl J Med 2000; 343:1778–1787. 5 Harris JW. Influenza occurring in pregnant women. JAMA 1919; 72:978–980. 6 Bland PB. Influenza in its relation to pregnancy and labor. Am J Obstet 1919; 79:184–197. 7 Public Health Laboratory Service. Deaths from Asian influenza, 1957. Br Med J 1958; 19:915–919. 8 Freeman DW, Barno A. Deaths from Asian influenza associated with pregnancy. Am J Obstet Gynecol 1959; 78:1172–1175. 9 Greenberg M, Jacobziner H, Pakter J, Weisl BAG. Maternal mortality in the epidemic of Asian influenza, New York City, 1957. Am J Obstet Gynecol 1958; 76:897–902. 10 Neuzil KM, Reed GW, Mitchel EF, et al. Impact of influenza on acute cardiopulmonary hospitalizations in pregnant women. Am J Epidemiol 1998; 148:1094–1102. 11 Hartert TV, Neuzil KM, Shintani AK, et al. Maternal morbidity and perinatal outcomes among pregnant women with respiratory hospitalizations during influenza season. Am J Obstet Gynecol 2003; 189:1705–1712. 12 Mullooly JP, Barker WH, Nolan TF. Risk of acute respiratory disease among pregnant women during influenza A epidemics. Public Health Rep 1986; 101:205–211. 13 Yawn DH, Pyeatte JC, Joseph JM, et al. Transplacental transfer of influenza virus. JAMA 1971; 216:1022–1023. 14 Acs N, Banhidy F, Puho E, Czeizel AE. Pregnancy complication and delivery outcomes of pregnant women with influenza. J Matern Fetal Neonatal Med 2006; 19:135–140. A retrospective, population-based, large control study that looked at complications and delivery outcomes for pregnant women with influenza. 15 Busby A, Dolk H, Armstrong B. Eye anomalies: seasonal variation and maternal viral infections. Epidemiology 2005; 16:317–322. 16 Brown AS, Begg MD, Gravenstein S, et al. Serologic evidence of prenatal influenza in the etiology of schizophrenia. Arch Gen Psychiatry 2004; 61:774–780. 17 ACOG Committee on Obstetric Practice. ACOG Committee Opinion. Influenza vaccination and treatment during pregnancy. Obstet Gynecol 2004; 104:1125–1126. 18 Roberts S, Hollier LM, Sheffield J, et al. Cost-effectiveness of universal influenza vaccination in a pregnant population. Obstet Gynecol 2006; 107:1323–1329. A decision analysis model that shows it is cost-effective to universally give the influenza vaccine to all pregnant women. 19 Lindsay L, Jackson LA, Savitz DA, et al. Community influenza activity and risk of acute influenza-like illness episodes among healthy unvaccinated pregnant and postpartum women. Am J Epidemiol 2006; 163:838–848. A retrospective chart review showing the cost-effectiveness of the influenza vaccine in pregnancy. 20 Deinard AS, Ogburn P Jr. A/NJ/8/76 influenza vaccination program: effects on maternal health and pregnancy outcome. Am J Obstet Gynecol 1981; 140:240–245. 21 Munoz FM, Greisinger AJ, Wehmanen OA, et al. Safety of influenza vaccination during pregnancy. Am J Obstet Gynecol 2005; 192:1098–1106. 22 Schrag SJ, Fiore AE, Gonik B, et al. Vaccination and perinatal infection prevention practices among obstetrician-gynecologists. Am J Obstet Gynecol 2003; 101:704–710. Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Viral respiratory disease in pregnancy Longman and Johnson 125 23 Wallis DH, Chin JL, Sur DKC. Influenza vaccination in pregnancy: current practices in a suburban community. J Am Board Fam Pract 2004; 17:287–291. 24 Wu P, Griffin MR, Richardson A, et al. Influenza vaccination during pregnancy: opinions and practices of obstetricians in an urban community. South Med J 2006; 99:823–828. 25 Center for Disease Control. Influenza vaccination in pregnancy: practices among obstetrician-gynecologists – United States, 2003–2004 influenza season. MMWR 2005; 54:1050–1052. A survey of obstetricians, performed by the ACOG and the CDC, which identified reasons for low influenza vaccination rates of pregnant women. 45 Bresson JL, Perronne C, Launay O, et al. Safety and immunogenicity of an inactivated split-virion influenza A/Vietnam/1194/2004 (H5N1) vaccine: phase I randomized trial. Lancet 2006; 367:1657–1664. A random, open-label, noncontrolled phase I trial of a H5N1 vaccine. 46 Shu Y, Yu H, Li D. Lethal Avian Influenza A (H5N1) infection in a pregnant woman in Anhui Province, China. N Engl J Med 2006; 354:1421–1422. The only reported case of a pregnant women with avian influenza. 47 Ksiazek TG, Erdman D, Goldsmith CS, et al. A novel coronavirus associated with severe acute respiratory syndrome. N Engl J Med 2003; 348:1953– 1966. 26 Tominson MW, Caruthers TJ, Whitty JE, et al. Does delivery improve maternal condition in the respiratory-compromised gravida? Obstet Gyencol 1998; 91: 108–111. 48 Drosten C, Gunther S, Preiser W, et al. Identification of a novel coronavirus in patients with severe acute respiratory syndrome. N Engl J Med 2003; 348: 1967–1976. 27 Micromedex1 Healthcare Series. http://micromedex.med.umich.edu/mdxcgi/ display.exe?CTL=E:\mdx\mdxcgi\MEGAT.SYS&SET=1C6D114F29D58C10 &SYS=6&T=2696&D=1&Q=0. [Accessed 5 September 2006] 49 Ng WF, Wong SF, Lam A, et al. The placentas of patients with severe acute respiratory syndrome: a pathophysiological evaluation. Pathology 2006; 38: 210–218. 28 Vernier VG, Harmon JB, Stump JM, et al. The toxicologic and pharmacologic properties of amantadine hydrochloride. Toxicol Appl Pharmacol 1969; 15: 642–665. 50 Hui DSC, Sung JJY. Severe acute respiratory syndrome. Chest 2003; 124:12–15. 29 Lamar JK, Calhoun FJ, Darr AG. Effects of amantadine hydrochloride on clearage and embryonic development in the rat and rabbit [abstract]. Toxicol Appl Pharmacol 1970; 17:272. 30 Rosa F. Amantadine pregnancy experience [letter]. Reproduct Toxicol 1994; 8:531. 31 Levy M, Pastuszak A, Koren G. Fetal outcome following intrauterine amantadine exposure. Reproduct Toxicol 1991; 5:79–81. 32 Golbe LI. Parkinson’s disease and pregnancy. Neurology 1987; 37:1245– 1249. 33 Pandit PB, Chitayat D, Jefferies AL, et al. Tibial hemimelia and tetralogy of fallot associated with first trimester exposure to amantadine. Reproduct Toxicol 1994; 8:89–92. 34 Avian influenza (‘bird flu’) – fact sheet. http://www.who.int/mediacentre/ factsheets/avian_influenza/en/. [Accessed 5 September 2006] A very descriptive and informative fact sheet on avian influenza. 35 Avian influenza (bird flu) – fact sheet – key facts about avian influenza (bird flu) and avian influenza A (H5N1) virus. http://www.cdc.gov/flu/avian/gen-info/ facts.htm. [Accessed 5 September 2006] Another very descriptive and informative fact sheet on avian influenza. 36 Center for Disease Control. Isolation of avian influenza A (H5N1) viruses from humans – Hong Kong, May–December 1997. JAMA 1998; 279:263–265. 37 Subbarao K, Klimov A, Katz J, et al. Characterization of an avian influenza A (H5N1) virus isolated from a child with a fatal respiratory illness. Science 1998; 393–396. 38 Ungchusak K, Auewarakul P, Dowell SF, et al. Probable person-to-person transmission of avian influenza A (H5N1). N Engl J Med 2005; 352:333–340. The first documented case of person-to-person transmission of H5N1. 39 Beigel JH, Farrar J, Han AM, et al. The Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5. Avian influenza A (H5N1) infection in humans. N Engl J Med 2005; 353:1374–1385. 40 Avian influenza. http://www.uhs.umich.edu/wellness/other/avianflu.html# what. [Accessed 5 September 2006] A very descriptive and informative fact sheet on avian influenza. 41 Wood JM, Major D, Daly J, et al. Vaccines against H5N1 influenza. Vaccine 2000; 18:579–580. 42 Stephenson I, Gust I, Pervikov Y, et al. Development of vaccines against influenza H5. Lancet Infect Dis 2006; 6:458–460. Identifies the difficulties of finding a vaccine against H5N1. 43 Li S, Liu C, Klimov A, et al. Recombinant influenza A virus vaccines for the pathogenic human A/Hong Kong/97 (H5N1) viruses. J Infect Dis 1999; 179:1132–1138. 44 Treanor JJ, Campbell JD, Zangwill KM, et al. Safety and immunogenicity of an inactivated subvirion influenza A (H5N1) vaccine. N Engl J Med 2006; 354:1343–1351. A multicenter, double-blind, placebo-based study for a H5N1 vaccine. 51 Stockman LJ, Lowther SA, Coy K, et al. SARS during pregnancy, United States. Emerging Infect Dis 2004; 10:1689–1690. 52 Robertson CA, Lowther SA, Birch T, et al. SARS and pregnancy: a case report. Emerging Infect Dis 2004; 10:345–348. 53 Poutanen SM, Low DE, Henry B, et al. Identification of severe acute respiratory syndrome in Canada. N Engl J Med 2003; 348:1995–2005. 54 Tsang KW, Ho PL, Ooi GC, et al. A cluster of severe acute respiratory syndrome in Hong Kong. N Engl J Med 2003; 348:1977–1985. 55 Li AM, Ng PC. Severe acute respiratory syndrome (SARS) in neonates and children. Arch Dis Child Fetal Neonatal Ed 2005; 90:F461–F465. Describes the triphasic pattern of the clinical course of SARS. 56 Peiris JSM, Chu CM, Cheng VCC, et al. Clinical progression and viral load in a community outbreak of coronavirus-associated SARS pneumonia: a prospective study. Lancet 2003; 361:1767–1772. 57 Lee N, Hui D, Wu A, et al. A major outbreak of severe acute respiratory syndrome in Hong Kong. N Engl J Med 2003; 348:1986–1994. 58 Center for Disease Control. Severe acute respiratory syndrome (SARS) and coronavirus testing – United States, 2003. JAMA 2003; 52:2203–2206. 59 Case definitions for surveillance of severe acute respiratory syndrome (SARS). http://www.who.int/csr/sars/casedefinition/en/print.htm. [Accessed 29 July 2006] 60 Epidemic and pandemic alert and response (EPR). http://www.who.int/csr/ sars/labmethods/en/. [Accessed 29 July 2006] 61 So LKY, Lau ACW, Yam LYC, et al. Development of a standard treatment protocol for severe acute respiratory syndrome. Lancet 2003; 361:1615– 1617. 62 Wong SF, Chow KM, Leung TN, et al. Pregnancy and perinatal outcomes of women with severe acute respiratory syndrome. Am J Obstet Gynecol 2004; 191:292–297. 63 Lam CM, Wong SF, Leung TN, et al. A case–controlled study comparing clinical course and outcomes of pregnant and nonpregnant women with severe acute respiratory syndrome. Br J Obstet Gynecol 2004; 111:771– 774. 64 Yudin MH, Steele DM, Sgro MD, et al. Severe acute respiratory syndrome in pregnancy. Obstet Gynecol 2005; 105:124–127. A Canadian case of SARS in a third-trimester pregnant woman successfully treated without ribavirin. 65 Kochhar DM, Penner JD, Knudsen TB. Embryotoxic, teratogenic, and metabolic effects of ribavirin in mice. Toxicol Appl Pharmacol 1980; 52:99–112. 66 Ferm VH, Willhite C, Kilham L. Teratogenic effects of ribavirin on hamster and rat embryos. Teratology 1978; 17:93–102. 67 Wong SF, Chow KM, de Swiet M. Severe acute respiratory syndrome and pregnancy. Br J Obstet Gynecol 2003; 110:641–642. 68 Shek CC, Ng PC, Fung GPG, et al. Infants born to mothers with severe acute respiratory syndrome. Pediatrics 2003; 112:e254–e256. Copyright © Lippincott Williams & Wilkins. 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