Pregnant women have started to receive invitations from GPs offering vaccination against swine flu, which offers protection for mother and unborn child.
Yet public concerns about the vaccine’s risks outweighing its benefits remain high — so much so that the Government is to distribute further advice for pregnant women next week. Numerous sets of guidance have been issued to women, health workers and GPs in recent months.
Here The Times offers a guide to the facts, the hearsay and the unfounded speculation surrounding H1N1 and vaccination in pregnancy.
? I am pregnant. Should I be considering having the vaccine? Yes. Pregnant women are one of the high-risk groups identified by the Government for priority vaccination. Vaccination is not compulsory but it is strongly recommended for the country’s 500,000 pregnant women, and to help protect their babies.
People under the age of 45 have been most affected by the pandemic — an age group that includes most pregnancies. Evidence of the impact of swine flu infection shows that within this group, pregnant women are at a higher risk of severe disease and flu-related hospital admissions.
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? But isn’t flu likely to be little more than a nasty cold? What are the risks? To date most people have a full recovery within a week, even without medical treatment. The most commonly reported symptoms include cough, fever, sore throat, muscle aches and headache.
However, flu is a serious viral infection, and a minority of patients develop severe illness, principally severe progressive pneumonia and heart and lung problems.
The World Health Organisation (WHO) states that pregnant women may be four to five times more likely to develop severe disease, and ten times more likely to need care in an intensive care unit compared with the general population. The risks increase with gestational age, with women in the third trimester particularly at risk.
The WHO states that between 7 and 10 per cent of all hospital patients are pregnant women in their second or third trimester. The Department of Health has not released figures for the number of pregnant women now in hospital with a swine flu infection. (As of this week there were about 700 people in English hospitals, with about one in five in critical care.) To date, 182 deaths in Britain have been directly linked to swine flu. Of these, at least 10 (5.5 per cent) have been pregnant women or women who have recently given birth — six in England, two in Scotland, and one each in Wales and Northern Ireland.
? So what should I be doing? From this week, GPs should have begun contacting pregnant women as well as other priority groups to begin community distribution of the vaccine. Roll-out has been steady but slow, with many practices so far receiving only one box of 500 doses when serving thousands of patients. Recent postal strikes have also delayed notification letters sent to patients. If you have not yet heard from your doctor, it is worth ringing the surgery.
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? What vaccine is being offered? The vaccine recommended for pregnant women by the Joint Committee on Vaccination and Immunisation is Pandemrix, manufactured by GlaxoSmithKline. The vaccine can be administered in a single dose, which appears to give adequate levels of antibodies against the H1N1 virus. A second vaccine, Celvapan, manufactured by Baxter, has also been ordered by the Government. However, it requires two doses, given three weeks apart, so does not confer protection as rapidly.
Both vaccines have been licensed for use in pregnant women, and at any stage of pregnancy, by the European Medicines Agency (EMEA), which considered evidence from trials involving thousands of people. All licensed vaccines have a high standard of safety.
? So have the vaccines been trialled on pregnant women? No. This has been seized upon by some to question their safety, and has spurred controversy. However, no vaccines are routinely tested on pregnant women. Vaccines are given to pregnant women when it is clinically necessary — such as polio, tetanus and seasonal flu vaccines. The safety of giving a particular vaccine is instead assessed from what is already known about its ingredients and the results of toxicity studies. Some non-pregnant women enrolled in trials do fall pregnant shortly after — these cases are followed up, with all information added to the assessment of possible risks. Any medication given to pregnant women is subject to extremely careful consideration on both clinical and ethical levels. The decision is made on a balance of benefit and risk. The Department of Health states that it has “no reason to believe there is a risk of harm from giving the swine flu vaccines in pregnancy”.
? So why have concerns been raised? There is a large body of evidence from seasonal flu vaccination programmes that immunisations similar to Celvapan are safe. The Pandemrix vaccine has been the subject of more discussion, and unfounded speculation, because it contains an adjuvant. An adjuvant is a chemical that enhances the immune response following vaccination, meaning that a lower dose of the vaccine is needed to produce the same level of protection. The adjuvant in Pandemrix is called squalene, which is extracted from fish oil.
There is less evidence on the use of adjuvanted vaccines in pregnant women. However, both vaccine and adjuvant have been the subject of thorough evaluation by the EMEA and the Department of Health, taking into account the severity of swine flu illness in pregnant women. In early June, the WHO reviewed the safety of adjuvants and found no significant safety concerns.
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? What is thiomersal and does it pose a risk? Thiomersal is a preservative used in Pandemrix. It is added to prevent bacterial contamination occurring. Thiomersal contains a small amount of mercury, which has been seized upon by some to cast further doubts on its safety.
This is unfounded. The Department of Health states that there is no evidence of risk from thiomersal in vaccines, including for children, pregnant women and their offspring.
? Are there any side-effects from the vaccines? The most common side-effects reported from the trials are minor: headaches, joint pain, muscle pain, fever and fatigue. It cannot cause swine flu as it does not contain a live virus. All vaccines can also cause redness, soreness and swelling at the site of the injection.
? If you deliver your baby before getting your flu jab, should you still receive it? Can a woman who is breast-feeding receive the vaccine?
Yes and yes. In addition to protecting women from infection, the vaccine may also help protect the infant. Breast-feeding is fully compatible with flu vaccination, and preventing maternal infection provides obvious secondary protection to the child.