In the autumn of 2009, there was a wave of swine flu caused by a new influenza virus, A (H1N1). Many young people and women became ill, but fortunately the pandemic was less serious than initially feared.
The vast majority of women who have influenza during pregnancy fully recover. However, pregnant women infected with influenza are at greater risk of complications, such as pneumonia and pulmonary failure, than other women. Severe complications can lead to miscarriage or premature birth. During the pandemic, the Norwegian health authorities therefore recommended that pregnant women in their 2nd and 3rd semester should be vaccinated. The risk of serious illness and death in pregnant women was considered greater than the risk of possible adverse effects of the pandemic vaccine. The same recommendation was given by the World Health Organization and most other countries with access to pandemic vaccines.
Several hundred of thousand pregnant women in Europe were vaccinated with Pandemrix during the autumn of 2009. So far, no unwanted effects for the pregnant women or their foetuses / children have been observed.
A registry study of Norwegian women who were pregnant during the influenza pandemic in 2009 showed that pregnant women who received the pandemic vaccine had no increased risk of stillbirth. However, pregnant women who had influenza had an increased risk of stillbirth. The study was published in the New England Journal of Medicine (Håberg et al., 2013).
Who is participating in NorFlu?
The NorFlu participants are women recruited from Oslo and Bergen, who were pregnant during the influenza pandemic of 2009-2010, and their children. About 3200 pregnant women chose to take part in NorFlu. In addition, almost 1 300 women and their children agreed to take part in a collaborative project between NorFlu and the Norwegian Mother and Child Cohort Study (MoBa).
In total, about 4500 mothers and their children are participating in NorFlu. In addition, 300 non-pregnant women were recruited as controls.
Women who did or did not have influenza, or who did or did not take the vaccine during pandemic are participating in the study. Participation is voluntary.
What does participating in NorFlu involve?
- Taking part in NorFlu involves completing questionnaires and giving a blood sample. Participants were asked to fill in two questionnaires before birth, and then when the child was 6 months, 18 months, 3 and 7 years old (see "Questionnaires in NorFlu"). A questionnaire at 9 years is planned autumn 2019. The women were asked for a blood sample at birth, as well as a blood sample from the umbilical cord after separation from the child. It may also be relevant to use other samples taken during pregnancy and after birth.
- Consent gives NorFlu permission to obtain information about the mother and child from the Medical Birth Registry. Information can also be obtained from other registries, such as the Notification System for Communicable Diseases, the Norwegian Immunisation Registry SYSVAK, the Norwegian Patient Registry, the Cancer Registry, the Cause of Death Registry, the Norwegian Prescription Database and primary care data. If the woman is also a participant in the Norwegian Mother and Child Cohort Study (MoBa), information can be obtained from this study in addition. The extent to which information is obtained from these records depends on which health conditions that are relevant to the NorFlu study.
- To obtain information from hospital records, registers in Statistics Norway or social security registers, NorFlu must obtain a specific new approval from the Regional Committee for Medical and Health Research Ethics in each case.
- Participants in NorFlu can be asked if they want to participate in sub-projects which involve the gathering of new information directly from the mother or child. Future studies are voluntary and require a new consent and new approval from the Regional Committee for Medical and Health Research Ethics. In 2013-2015 a clinical study of 3-4 year olds was carried out.
Only unidentified material will be made available to the researchers. It will not be possible to identify participants in NorFlu when the research results are published.
Participants have the right to access all health information that is registered about themselves and have the right to correct any errors. They can withdraw from the study at any time without stating a reason, and may request deletion of collected information or decide that biological samples will not be used for further research.
All participants signed a consent form that applies for both mother and child until the child reaches 16 years of age. At this point, the child must give their autonomous consent to any further participation.
Safe storage of information
Blood samples are stored in a biobank at the Norwegian Institute of Public Health, and then analysed in an unidentified form. The information from the questionnaires is stored in a similar manner without name or personal identity number. A code number links the participant with the information through a coupling key. This key is stored separately from the rest of the material, and only a few authorised project staff have access to it. Information and samples will be deleted at the end of the project, which is currently set for 2025. However, a continuation of the approvals is possible.
Responsibility for the study
The Norwegian Institute of Public Health is responsible for NorFlu and the project manager is Lill Trogstad. The recruitment of pregnant women was conducted in collaboration with Haukeland University Hospital in Bergen, Oslo University Hospital and Asker and Bærum Hospital. NorFlu is approved by the Regional Committee for Medical and Health Research Ethics. Blood tests and information collected will be used solely for research in accordance with the approval of the Regional Committee for Medical and Health Research Ethics.
The Norwegian Institute of Public Health received 7 million Norwegian kroner from the Ministry of Health and Care Services to start the project.