UOA02-04: Underpinning Evidence-based Policy for Management of Influenza in Pregnant Women
Submitting InstitutionUniversity of Oxford
Unit of AssessmentPublic Health, Health Services and Primary Care
Summary Impact TypePolitical
Research Subject Area(s)
Medical and Health Sciences: Public Health and Health Services
Summary of the impact
Researchers at the University of Oxford instituted a rapid study of
pregnant women hospitalised across the UK with 2009/H1N1 infection, which
demonstrated that early antiviral treatment improved maternal outcomes of
infection and led to actions by the Department of Health to ensure rapid
availability of antivirals specifically for pregnant women. The poor
maternal and perinatal outcomes identified by this study also led to an
on-going policy change, so that all pregnant women in the UK are now
recommended to receive annual immunisation against seasonal influenza.
Following the outbreak of the 2009/H1N1 influenza pandemic, pregnant
women were identified as a probable high-risk group. The existence of UK
Obstetric Surveillance System (UKOSS)  developed and led by Professor
Marian Knight and colleagues at the National Perinatal Epidemiology Unit,
University of Oxford, enabled the rapid initiation of a study of pregnant
women hospitalised across the UK with 2009/H1N1 infection . Data were
analysed on a monthly basis to inform the development of on-going policy
and guidance issued by the Department of Health. This allowed for
real-time changes to policy and guidelines as the data accumulated,
enabling a rapid response to the emerging pandemic.
The study findings demonstrated that early antiviral treatment for
pregnant women led to a 90% reduction in the odds of admission for
critical care. This resulted in actions by the Department of Health to
ensure rapid availability of antivirals specifically for pregnant women,
through the modification of the clinical algorithms in use, enabling
availability of antivirals for pregnant women through the National
Pandemic Flu Service. Guidance for obstetricians and other clinicians
involved in the care of pregnant women was also modified .
The poor maternal and perinatal outcomes identified by the study, showing
a five times increase in the risk of perinatal death and a more than three
times increase in the risk of premature birth amongst the infants of
infected women, also led to a change in immunisation policy in the UK
during the course of the pandemic. The updated policy classified pregnant
women as an "at-risk group" eligible for influenza vaccination [3,4].
These data have also led to an on-going policy change, so that all
pregnant women in the UK are now recommended to receive an annual
immunisation against seasonal influenza. The European Centre for Disease
Control and Prevention (ECDC) also issued a subsequent recommendation,
based on UKOSS data, that universal influenza immunisation for pregnant
women should be offered throughout Europe [see reference G in impact
References to the research
. Knight M, Kurinczuk JJ, Tuffnell D, Brocklehurst P. The UK Obstetric
Surveillance System for rare disorders of pregnancy. Br J Obstet Gynaecol
2005; 112: 263-5.
PubMed ID: 15713136. Paper describing the establishment of the UK
Obstetric Surveillance System.
. Yates L, Pierce M, Stephens S, Mill AC, Spark P, Kurinczuk JJ,
Valappil M, Brocklehurst P, Thomas SH, Knight M. Influenza A/H1N1v in
pregnancy: an investigation of the characteristics and management of
affected women and the relationship to pregnancy outcome for mother and
infant. Health Technol Assess 2010;14:109-82.
PubMed ID: 20630123. http://www.hta.ac.uk/execsumm/summ1434-02.shtml
[accessed 9/10/13]. Monograph describing the maternal outcomes of
2009/H1N1 influenza. Oxford researchers led the secondary care study.
. Knight M, Pierce M, Seppelt I, Kurinczuk JJ, Spark P, Brocklehurst
P, McLintock C, Sullivan E on behalf of the UK's Obstetric Surveillance
System, the ANZIC Influenza Investigators, and the Australasian Maternity
Outcomes Surveillance System. Critical illness with AH1N1v influenza in
pregnancy: a comparison of two population-based cohorts. Br J Obstet
Gynaecol 2011;118:232-9. doi: 10.1111/j.1471-0528.2010.02736.x.
PubMed ID: 21040393. Paper showing better outcomes of 2009/H1N1
influenza in the UK compared to Australasia, after public health
measures were introduced.
. Pierce M, Kurinczuk JJ, Spark P, Brocklehurst P, Knight M on behalf
of UKOSS. Perinatal outcomes after maternal 2009/H1N1 infection: a
national cohort study. Br Med J 2011 Jun 14;342:d3214. doi:
10.1136/bmj.d3214. PubMed ID: 21672992. Paper detailing the
perinatal outcomes of 2009/H1N1 influenza, after all on-going
pregnancies were completed.
This research was funded by the UK National Institute for Health Research
Health Technology Assessment (HTA) programme.
Details of the impact
The key to being able to rapidly mount a study of pregnant women,
hospitalised with 2009/H1N1 pandemic influenza, was the prior
establishment in 2005 of the novel UKOSS system, which allows for rapid
institution of research into pregnancy complications in the event of a
public health emergency such as this. For the influenza study, data were
analysed cumulatively on a monthly basis, enabling Professor Knight to
feedback results in real-time via weekly teleconferences and monthly
meetings at the Department of Health. In this way the UKOSS findings were
central to immediate policy development, for guidance on the management of
pregnant women infected the with 2009/H1N1 virus, as the course of the
pandemic evolved [A, B, C]. The UKOSS results indicated that pregnant
women treated earlier with antiviral therapy had better maternal and
perinatal outcomes than those treated later in their clinical course or
not at all. National advice and the clinical algorithm was changed as a
result leading to the earlier initiation of antiviral therapy particularly
for pregnant women and action by the Department of Health to ensure the
availability of antiviral therapy to pregnant women through the National
Pandemic Flu Service and Antiviral Collection Points [C].
The extent of maternal morbidity, and maternal and perinatal deaths
quantified by the UKOSS study, contributed to the change in immunisation
policy in the UK during the course of the pandemic to actively offer
pregnant women immunisation. This policy change has now been adopted as an
on-going recommendation that annually all pregnant women should be
immunised against seasonal influenza [D, E]. The number of pregnant women
immunised against influenza in England has subsequently increased, from
118,000 in 2009/10, to 124,000 in 2010/11 and 196,000 in 2011/12 [F].
The impact of the research was achieved by the direct input of real-time
research results by Professor Marian Knight into the decision making
systems at the Department of Health for England. Results were also shared
with the Influenza planning group at the Royal College of Obstetricians
and Gynaecologists during the course of the evolving pandemic. Later
impact is demonstrated by the subsequent recommendation, which
incorporated the study data, issued by the European Centre for Disease
Control and Prevention (ECDC). The recommendation states that universal
influenza immunisation for pregnant women should be offered throughout
Once the pandemic had abated it became clear from data collected by UKOSS
and the National Confidential Enquiry into Maternal Deaths that 13
pregnant women in the UK had died as a direct result of 2009/H1N1
influenza virus infection. These deaths could have been prevented by prior
immunisation. In addition, the study results suggested that early
treatment with antiviral medication led to a 90% reduction in the odds of
admission for critical care. The resulting substantial changes in
practice, which were instituted as a result of the UKOSS study findings,
were, and continue to be, instrumental in preventing the deaths and
serious morbidity for pregnant women and their babies in the UK and
elsewhere. The study is referenced in guidance for critical care
clinicians [H]. It is also referenced in current media campaigns to
highlight the importance of on-going immunisation to women [I], and in
policy documents recommending immunisation against influenza in pregnancy
in countries other than the UK [J].
Sources to corroborate the impact
[A]. Minutes and action logs available from the Influenza Clinical
Information Network (FLU-CIN) meetings/teleconferences. These
documents demonstrate the use of the study data to inform policy
development during the H1N1 influenza pandemic.
[B]. Factual statement provided by the Department of Health Clinical
Advisor. Written statement describing the use made of the study
data to develop policy and clinical guidelines.
[C]. H1N1 (2009) winter flu: Updated guidance for providers of maternity
services. London: Department of Health 2011. http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1294740886540
[accessed 4/11/13]. This is the key Department of Health policy
document describing immunisation and antiviral prescription
[accessed 9/10/13]. This immunisation campaign article references
the BMJ paper and advises women to get the vaccine.
[accessed 9/10/13]. The Health Protection Agency link to vaccine
uptake information for 2009-2012.
Book-Chapter-19-v4_71.pdf [accessed 4/11/13]. Department of
Health guidance on immunisation for influenza in pregnancy (updated
for 2012/13 winter influenza season). See page 202.
%20of%20children%20and%20pregnant%20women.pdf [accessed 4/10/13]. This
is the ECDC European advice that all women should be immunised against
influenza in pregnancy. See pages 2, 3, 12, 14.
[accessed 4/11/13]. Guidance from the Health Protection Agency on
critical care management of adults with influenza with particular
reference to H1N1.
[accessed 9/10/13]. Guardian article citing the government campaign
to encourage women to have immunisation against seasonal influenza.
[accessed 4/11/13]. Guidance from the Republic of Ireland citing
the study and recommending immunisation against seasonal influenza for