The Chief Medical Officer was more passionate than I've ever seen her before. Nine babies have died this year in England and Wales from whooping cough. We can do something about it and we must.
Most pregnant women nowadays will never have seen a baby with whooping cough. The CMO, Dame Sally Davies, and the Director of Vaccination, Professor David Salisbury have both treated babies coughing so hard and so long that they have to gasp desperately to get their breath, sounding the heart-wrenching "whoop" that gave the infection its name. Some of them died.
Back in the 1950s, around 100,000 people a year got whooping cough. But now vaccination (at two months of age, with a booster at three and a bit) has cut numbers dramatically to a few hundred a year.
But this year there's a new epidemic. No-one knows why - vaccination coverage is 95%, higher than ever before. But still, so far this year in England and Wales 302 babies under 12 weeks got whooping cough and nine of them died.
In all there have been 4,791 cases this year - four times more than in the whole of last year.
Babies are most vulnerable and Dame Sally is determined to do something about it. But what?
They considered vaccinating babies earlier than two months. Trouble is that before eight weeks, babies' body defences aren't mature: their immune system can't make antibodies to fight off the infection like adults do when they're vaccinated.
The trick is to use their mother's bodies to make the antibodies for the babies. So from Monday, GPs and midwives will be offering to vaccinate pregnant women between 28 and 38 weeks into their pregnancy.
Vaccinated pregnant women won't get infected themselves and pass on the infection to their babies. But also they will produce antibodies in their bodies which will cross the placenta and give their babies immunity for the eight weeks when they're too young to be vaccinated themselves.
There is no single vaccine against whooping cough. So they're going to use one called Repevax, which combines vaccines for whooping cough, diphtheria, tetanus and polio.
Pregnant women, however, are reluctant to put anything in their bodies that might harm their babies - even a small glass of wine, let alone a vaccine. Dame Sally knows she must persuade them that the vaccine is safe.
And this is where she gets passionate. She's adamant her expert advisers have given the vaccine a clean bill of health. They have "no concerns about the safety of this vaccine for pregnant women and their babies". Its the same as the booster given to three-year olds. It has already been used for pregnant women in the US. It has been given safely to pregnant women in trials.
It's evidence that has convinced Dame Sally that the only way pregnant women have of protecting their babies against a horrible disease that has claimed 10 young lives this year is by getting the vaccination.
GPs surgeries already have stocks of the vaccine. All the relevant medical colleges are behind the scheme. However, it will only work if pregnant women come forward, overcoming any worries they may have.
The government has clarified that there have been 9 deaths from whooping cough in England and Wales.