8:32am UK, Thursday October 15, 2009

Thomas Moore, Sky News health correspondent

Pregnant women in Britain are to get a form of swine flu vaccine that is not recommended by the World Health Organisation (WHO).

The vaccine Pandemrix, which makes up the bulk of NHS supply, contains a chemical called an adjuvant that has never been tested on mums-to-be.

According to the WHO Strategic Advisory Group, pregnant women should be given adjuvant-free formulations of the vaccine whenever possible.

But the Department of Health's Director of Immunisations Professor David Salisbury said that even though the NHS has stocks of an alternative vaccine called Celvapan, it will not be prioritised for pregnant women

He said: "If the virus is increasing, as it has been recently and we had the supply of one vaccine ahead of the other, then we have to make a judgement that says pregnant women are at high risk and they need to be protected.

"And in those circumstances I would recommend whatever is available to hand to protect them."

The Department of Health says pregnant women are four times more likely to suffer serious complications if they catch swine flu and vaccination is essential.

It insists Pandemrix is safe and licensed for mums-to-be.

However, the licence was granted by medicine regulators based on clinical trials in healthy adults.

The vaccine was developed rapidly

University College London vaccine expert Dr Tarit Mukhopadhyay said there was no evidence of harm from adjuvants, but added that in the absence of formal clinical trials in pregnancy, they should not be used.

He said: "We don't know what could go wrong.

"There could be overstimulation of the immune system or actually nothing may go wrong at all.

"The problem is that not enough pregnant women have had this adjuvant tested on them. So we are going to err on the side of caution and recommend pregnant women take the unadjuvanted vaccine instead."

The controversy will do nothing to ease the concerns that pregnant women already have about vaccination.

Natalie Lisbona, who is 30 weeks pregnant, said: "There are no tests on pregnant women, so what is it going to do to the foetus?

"There doesn't seem to be clear evidence at the moment. They have rushed this vaccine through so quickly."