(Press-News.org) CHICAGO – In studies examining the risk of adverse outcomes after receipt of the influenza A(H1N1) vaccine, infants exposed to the vaccine in utero did not have a significantly increased risk of major birth defects, preterm birth, or fetal growth restriction; while in another, study researchers found a small increased risk in adults of the nervous system disorder, Guillain-Barre syndrome, during the 4 to 8 weeks after vaccination, according to 2 studies in the July 11 issue of JAMA.
In the first study, Björn Pasternak, M.D., Ph.D., of the Statens Serum Institut, Copenhagen, Denmark and colleagues investigated whether exposure to an adjuvanted influenza A(H1N1)pdm09 vaccine during pregnancy was associated with increased risk of major birth defects, preterm birth, and fetal growth restriction. According to background information in the article, the 2009 influenza A(H1N1) pandemic put pregnant women at increased risk of illness, death, and poor pregnancy outcomes. "Pregnant women were among the main target groups prioritized for vaccination against influenza A(H1N1)pdm09, and an estimated 2.4 million women were vaccinated during pregnancy in the United States alone. However, assessment of the fetal safety of H1N1 vaccination in pregnancy has been limited to a few pharmacovigilance reports and descriptive cohort studies."
The registry-based study included all live-born singleton infants in Denmark delivered between November 2, 2009, and September 30, 2010. The researchers estimated the prevalence odds ratios of adverse fetal outcomes, comparing infants exposed and unexposed to an AS03-adjuvanted influenza A(H1N1)pdm09 vaccine during pregnancy. Following exclusions, a group of 53,432 live-born infants was identified with 6,989 (13.1 percent) exposed to the vaccine during pregnancy.
In a propensity score-matched analysis of 330 infants exposed to the vaccine in the first trimester of pregnancy and 330 unexposed, there were 18 infants (5.5 percent) diagnosed with a major birth defect among those exposed compared with 15 (4.5 percent) among the unexposed. Among infants exposed to the H1N1 vaccine in the first trimester, 31 (9.4 percent) were born preterm compared with 24 (7.3 percent) among the unexposed. Preterm birth occurred in 302 of 6,543 infants (4.6 percent) with second- or third-trimester exposure, compared with 295 of 6,366 unexposed infants (4.6 percent). "Taking gestational age into account, there was no increased risk of small size for gestational age associated with vaccination in the first (25 [7.6 percent] exposed vs. 31 [9.4 percent] unexposed) or the second or third trimester (641 [9.7 percent] exposed vs. 657 [9.9 percent] unexposed)," the researchers write.
"In conclusion, this nationwide cohort study in Denmark found no significant associations between exposure to an AS03-adjuvanted influenza A(H1N1)pdm09 vaccine in pregnancy and risk of adverse fetal outcomes including major birth defects, preterm birth, and growth restriction. Although the data provide robust evidence of safety with respect to outcomes associated with second- or third-trimester exposure, results from analyses of first-trimester exposure should be viewed as preliminary and need confirmation. Further research also needs to address risk of specific birth defects as well as effectiveness of H1N1 vaccination in pregnancy."
INFORMATION:
(JAMA. 2012;308[2]:165-174. Available pre-embargo to the media at http://media.jamanetwork.com)
Editor's Note: This work was funded by the Danish Medical Research Council. All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Please Note: For this study, there will be multimedia content available, including the JAMA Report video, embedded and downloadable video, audio files, text, documents, and related links. This content will be available at 3 p.m. CT Tuesday, July 10 at this link.
END
Guillain-Barre syndrome (GBS) is usually characterized by rapidly developing motor weakness and areflexia (the absence of reflexes). "The disease is thought to be autoimmune and triggered by a stimulus of external origin. In 1976-1977, an unusually high rate of GBS was identified in the United States following the administration of inactivated 'swine' influenza A(H1N1) vaccines. In 2003, the Institute of Medicine (IOM) concluded that the evidence favored acceptance of a causal relationship between the 1976 swine influenza vaccines and GBS in adults. Studies of seasonal ...
Among intermediate- to high-risk patients undergoing coronary artery bypass graft surgery, administration of the agent acadesine to regulate adenosine (a naturally occurring chemical that dilates blood flow and can improve coronary blood flow and perfusion) did not reduce all-cause death, nonfatal stroke, or need for mechanical support for ventricular dysfunction, for approximately a month after surgery, according to a study in the July 11 issue of JAMA.
"Despite improvements in myocardial protection and perioperative care, the risk of death is still substantial in the ...
Patients who had surgery for periampullary cancer (a variety of types of cancer that are located in and near the head of the pancreas, including an area called the ampulla where the bile duct joins up with the pancreatic duct to empty their secretions into the upper small intestine) and received chemotherapy had a statistically significant survival benefit, compared to patients who did not receive chemotherapy, after adjusting for prognostic variables, according to a study in the July 11 issue of JAMA.
Periampullary carcinomas arise from the head of the pancreas. "The ...
In this week's PLoS Medicine, Julia Hussein from the University of Aberdeen in Scotland and colleagues assess the evidence for the effectiveness of interventions that aim to help pregnant women reach health facilities during an emergency in developing country settings. In a systematic review of the literature they found that the level of evidence for emergency obstetric referral interventions was poor and that limitations in the design of individual studies made determining the effect of referral interventions on outcomes difficult.
The authors note, "[d]espite the wealth ...
In a new article published this week that forms part of the PLoS Medicine series on Global Mental Health Practice, Shoba Raja and colleagues report their case study of implementing the "BasicNeeds" model of mental health and development in Nepal, which emphasizes user empowerment, community development, strengthening of health systems, and policy influencing.
The authors say their model works in partnership with governments to provide the "great push" that is required to set up services where mental health and development have not yet been a priority. The authors report ...
Insecticide resistance is threatening the effectiveness of insecticide-treated bed nets and indoor insecticide sprays to control adult mosquito vectors, and so more sustainable integrated management strategies that use optimal suites of control tactics are needed. These are the arguments of Willem Takken from the Wageningen University and Research Centre in The Netherlands and colleagues in this week's PLoS Medicine.
Experience in agriculture suggests that such integrated approaches can provide more effective and durable pest management, say the authors, which will require ...
DURHAM, N.C. – A drug designed to shield the heart from injury during bypass surgery failed to reduce deaths, strokes and other serious events among patients at high risk of complications, according to a large, prospective study lead by researchers at Duke University Medical Center.
But the international study also produced a surprising silver lining. As reported in the July 11 issue of the Journal of the American Medical Association, the researchers discovered that complications among bypass surgery patients were far less frequent than previously reported.
"We expected ...
People who are born deaf process the sense of touch differently than people who are born with normal hearing, according to research funded by the National Institutes of Health. The finding reveals how the early loss of a sense— in this case hearing—affects brain development. It adds to a growing list of discoveries that confirm the impact of experiences and outside influences in molding the developing brain. The study is published in the July 11 online issue of The Journal of Neuroscience.
The researchers, Christina M. Karns, Ph.D., a postdoctoral research associate in ...
The cancer drug bevacizumab (Avastin®) offers only a modest benefit in delaying disease progression in patients with advanced stage breast cancer, according to a systematic review by Cochrane researchers. The researchers assessed the efficacy of bevacizumab in combination with chemotherapy, an established cancer treatment in this indication, and found no overall survival benefit when adding bevacizumab to chemotherapy.
Breast cancer is the most common cause of cancer death among women. If it spreads to other parts of the body it is referred to as "metastatic" and the ...
Taking iron supplements one to three times a week instead of every day is just as effective at preventing anaemia in pregnant women, according to the findings of a new Cochrane systematic review. The authors of the review also showed that women experienced fewer side effects when taking iron supplements intermittently rather than daily.
Lack of iron can cause anaemia in pregnant women, potentially increasing the risk of complications at delivery. It may also be harmful to their babies, through increased risk of low birth weight and even delayed growth and development ...
