versión On-line ISSN 2078-5135
SAMJ, S. Afr. med. j. vol.100 no.4 Cape Town abr. 2010
Pandemic flu (H1N1) 2009 and pregnancy
To the Editor: We welcome the recommendations by Schoub et al.1 and advertisements in local newspapers highlighting the importance of influenza vaccination (Cape Times 17 February 2010), but are concerned that there is no unified strategy to ensure that all pregnant women are offered influenza vaccine and have access to antivirals should they develop symptoms of infection.
A striking feature of the pandemic H1N1 infection has been the predilection of severe disease in pregnant women. This is not surprising as pregnancy causes immunological and physiological changes which are likely to contribute to an increased susceptibility to influenza infection and an excessive risk of influenza-related morbidity and mortality.2 We have previously highlighted the problem of H1N1 in South Africa in pregnant women.3
Antivirals oseltamivir and zanamivir are effective against H1N1, and both may be used in pregnancy.2 Despite a lack of formal trials in pregnancy, both have been widely used in the second and third trimester without proven adverse effects on the mother or teratogenic effects on the unborn child. Their use is justified on the basis that the potential benefit to the mother outweighs any potential risk to the fetus.4 However, antiviral therapy must be initiated early to be effective, posing a considerable logistical challenge.5 Vaccination is the most important weapon in preventing influenza infection and its sequelae in pregnant women. Pregnant women have been prioritised for vaccination in industrialised countries during the 2009/2010 season. The inactivated influenza vaccine is void of harmful effects on maternal or neonatal health.6 Since pandemic H1N1 vaccines are produced using the same manufacturing and licensing process as seasonal influenza vaccines, it is anticipated that they will have similar safety profiles, with serious adverse events after vaccination being uncommon. However, ongoing monitoring and further data are needed.
Influenza vaccine uptake7 in the northern hemisphere has been poor even in the face of the pandemic.8 The incorporation of the pandemic strain into the regular seasonal vaccine for the southern hemisphere requires a new focus on vaccination by health care providers who do not deal with the 'classic' risk groups (mostly the elderly and chronically ill) and who have little experience and lack awareness of the topic.
We urge public health officials to accelerate and intensify planning for the 2010 influenza season, and suggest:
widespread and strategic informing of health care professionals - particularly those primarily involved in the care of pregnant women - on the importance of vaccinating pregnant women against influenza
increasing efforts to improve influenza vaccine uptake by pregnant women by community-based information campaigns
informing health care professionals on the need for timely diagnosis and immediate antiviral treatment of pregnant women with suspected influenza
training and equipping all antenatal clinics to diagnose and treat women with symptoms of acute influenza.
Good uptake of the vaccination requires early action to ensure that health care workers are aware of the risks associated with H1N1 in pregnant women and their potential reluctance to be vaccinated. Given our scarce health care resources, our priority must be to keep pregnant women well and out of hospital. Vaccination is central to any prevention strategy, while neuramidase inhibitors may reduce the severity of disease, reducing the likelihood that women may need hospitalisation.
M I Andersson
G van Zyl
Division of Medical Virology
Faculty of Health Sciences
Stellenbosch University and NHLS Tygerberg, W Cape
Department of Obstetrics and Gynaecology
Stellenbosch University and Tygerberg Hospital
1. Department of Health. Recommendations pertaining to the use of viral vaccines: Influenza 2010. S Afr Med J 2010; 100(2): 88-89. [ Links ]
2. Rasmussen SA, Jamieson DJ, Macfarlane K, Cragan JD, Williams J, Henderson Z. Pandemic influenza and pregnant women: summary of a meeting of experts. Am J Public Health 2009; 99 Suppl 2: S248-S254. [ Links ]
3. Langenegger E, Coetzee A, Jacobs S, le Roux A, Theron G. Severe acute respiratory infection with influenza A (H1N1) during pregnancy. S Afr Med J 2009; 99(10): 713-714, 716. [ Links ]
4. Elliott EJ. Pregnancy and pandemic flu. Clin Infect Dis 2010; 50(5): 691-692. [ Links ]
5. Maritz J, Maree L, Preiser W. Pandemic influenza A (H1N1) 2009: the experience of the first six months. Clin Chem Lab Med 2010; 48(1): 11-21. [ Links ]
6. Pool V, Iskander J. Safety of influenza vaccination during pregnancy. Am J Obstet Gynecol 2006; 194(4): 1200. [ Links ]
7. Munoz FM, Greisinger AJ, Wehmanen OA, et al. Safety of influenza vaccination during pregnancy. Am J Obstet Gynecol 2005; 192(4): 1098-1106. [ Links ]
8. Beigi RH, Switzer GE, Meyn LA. Acceptance of a pandemic avian influenza vaccine in pregnancy. J Reprod Med 2009; 54(6): 341-346. [ Links ]