News Archives |
Volume 4 No 47; 26 November 2010
- Summary of antenatal screening for infectious diseases: 2005-2009
- Committee on the Medical Effects of Air Pollutants (COMEAP) statement on the question ‘Does Outdoor Air Pollution Cause Asthma?’
Summary of antenatal screening for infectious diseases: 2005-2009
Routine antenatal care for pregnant women includes screening for hepatitis B, HIV, syphilis infection and rubella susceptibility. Infectious diseases in pregnancy can have serious consequences for both the mother and child if left untreated. However, if the infection is diagnosed promptly, interventions can be put in place which limit the risk of transmission of the infection to the child. Prompt diagnosis also allows the mother to enter the appropriate pathways of care and receive the necessary treatment.
The 2003 Department of Health's Screening for Infectious Diseases in Pregnancy Standards set a target of 90% for the uptake of antenatal screening for HIV [1]. This was the only infection with such a target until the 2010 revised Standards [2] retained this 90% uptake target as a reference point for all four infections. In 2005, the National Antenatal Infections Screening Monitoring (NAISM) programme began monitoring the uptake and test results of antenatal screening for the four infections in England.
Uptake of antenatal screening
Uptake of antenatal screening is calculated as the proportion of women booked for antenatal care who have a screening test. Screening uptake increased significantly for all four infections between 2005 and 2009 (figure 1), with the greatest increase in screening seen for HIV, from 88.9% (500,203/562,469) to 95.1% (662,849/697,354). The 90% uptake target for HIV was met in 2006 at a national level and all regions achieved the target in 2008. Even though uptake is now above the national target, vigilance is still paramount in order to continue the prevention of mother-to-child transmission of HIV. In 2009, screening uptake for hepatitis B, syphilis and rubella susceptibility was 95.6% (672,989/704,132), 96.0% (671,159/699,225) and 95.8% (662,821/ 691,543) respectively.
Figure 1. National reported uptake of antenatal screening by infection in England: 2005-2009 
Proportion of pregnant women screening positive or susceptible
The proportion of women who undertook screening and tested positive for hepatitis B, HIV, and syphilis remained relatively stable over the period 2005-2009 (figure 2). There was regional variation with the highest positivity rates in London for each infection. Nationally in 2009, 0.46% (3,208/699,795) of antenatal women screened positive for hepatitis B, 0.18% (1,275/690,695) for HIV and 0.16% (1,142/696,371) for syphilis (see table). There was a significant increase in the proportion of women who screened susceptible to rubella infection (see figure 2). In 2009, 4.28% (29,308/683,992) of women screened were susceptible to rubella, compared to 2.59% (13,432/518,302) in 2005. The reasons for this increase in susceptibility need to be investigated further.
Figure 2 : Proportion of pregnant women screening positive for hepatitis B, HIV and syphilis and susceptible to rubella infection in England: 2005-2009* 
In 2009, information on women previously diagnosed with hepatitis B and HIV were collected for the first time. The new 2010 Standards [2] state that women already known to be positive for hepatitis B or HIV should not be offered antenatal screening for that infection; however, this was not previously the case. Therefore, in 2009, data were collected on the number of women who were previously diagnosed, and of these, how many were screened again in the current pregnancy. Two figures were then calculated: the proportion of women newly diagnosed with hepatitis B or HIV and the total proportion of women positive for these infections regardless of whether they were screened again (see table). Some maternity units could not supply information on women who were previously diagnosed and therefore their data were excluded from the newly diagnosed proportion. For diagnoses where all information was available, 55% (1,255/2,280) of diagnosed hepatitis B-infected women and 41% (406/985) of diagnosed HIV-infected women were identified through antenatal screening in the current pregnancy. These are therefore women who would not have been diagnosed in the absence of national antenatal screening and whose babies would have been at risk of transmission of infection through mother-to-child transmission.
Proportion of pregnant women screening positive for hepatitis B, HIV or syphilis or susceptible to rubella infection in England: 2009
| Hepatitis B | HIV | Syphilis |
Rubella |
|||
|---|---|---|---|---|---|---|
% positive* |
% newly diagnosed** |
% positive* |
% newly diagnosed** |
% positive*** |
% susceptible**** |
|
East Midlands |
0.29 |
0.15 |
0.10 |
0.03 |
0.13 |
2.72 |
East of England |
0.28 |
0.17 |
0.14 |
0.08 |
0.09 |
3.40 |
London |
1.06 |
0.54 |
0.40 |
0.15 |
0.39 |
4.83 |
North East |
0.24 |
0.19 |
0.06 |
0.02 |
0.11 |
6.34 |
North West |
0.30 |
0.19 |
0.11 |
0.07 |
0.09 |
3.09 |
South East |
0.27 |
0.16 |
0.12 |
0.05 |
0.09 |
4.84 |
South West |
0.18 |
0.12 |
0.07 |
0.02 |
0.06 |
3.81 |
West Midlands |
0.40 |
0.20 |
0.17 |
0.09 |
0.17 |
3.51 |
Yorkshire & Humber |
0.35 |
0.18 |
0.18 |
0.06 |
0.09 |
5.72 |
| National | 0.46 |
0.23 |
0.18 |
0.07 |
0.16 |
4.28 |
Copies of the most recent annual report are available electronically at: http://www.hpa.org.uk/web/HPAweb&HPAwebStandard/HPAweb_C/1245581538007.
References
1. Department of Health. Screening for infectious diseases in pregnancy: Standards to support the UK antenatal screening programme, 2003.
2. National Screening Committee. Infectious Diseases in Pregnancy Screening Programme Standards, 2010.
The Committee on the Medical Effects of Air Pollutants (COMEAP) has published a statement [1] together with supporting papers, following its consideration of the suggestion that exposure to outdoor air pollutants might be a primary cause of asthma.
In an earlier report, published in 1995, COMEAP concluded that exposure to outdoor air pollutants might play a part in triggering asthma attacks in people who already have the condition. The new statement, taking account of more recent evidence, updates the earlier work and also considers whether air pollution contributes to the development of asthma in people who have previously not suffered from the disease. It concludes: “It is unlikely that exposure to outdoor air pollutants causes asthma in the general population. However, it is possible that in a small group of those who suffer from asthma, who also live near busy roads, exposure to traffic generated air pollutants, largely from trucks, may have played a small part in causing their disease”.
The full statement [2] and related documents – including an overview of the evidence and working papers considered – are available on COMEAP's new website [3] which also provides access to related meeting papers and minutes, and includes a number of pages dedicated to non-air pollution scientists.
COMEAP is an advisory committee of independent experts that provides advice to Government Departments and Agencies on all matters concerning the potential toxicity and effects upon health of air pollutants. COMEAP is supported by a secretariat provided by the Health Protection Agency.
References
1. “Air pollution and asthma - a link considered“ COMEAP press release [49 kB PDF], 25 November 2010.
2. COMEAP statement, “Does outdoor air pollution cause asthma ?” [76 kB PDF]
Available at: http://www.comeap.org.uk/documents/118-asthma-statement.html.