Virus hits 10 after vaccinations

12th January 2006

By Anna Bowden

Ten people have become infected with the potentially deadly meningococcal B virus despite having been vaccinated and today health officials are expected to announce that Bay babies will need a fourth vaccination before they are fully protected.

Since the meningococcal B vaccination programme was rolled out throughout the country to under 20-year-olds, 10 people have become infected including a baby.

As reported in the Bay of Plenty Times last June, the Ministry of Health is considering the possibility of a fourth "booster" vaccination for children aged under six months.

Bay of Plenty District Health Board's project manager John McRae said he was not aware that any of the "breakthrough" cases were in the Western Bay but he was concerned with the number of incomplete vaccinations for the region's youngest children.

"My particular concern is that we still have a number of six week to five-year-olds who are not coming in to be vaccinated," he said.

He urged parents to remember all three doses were required to effectively immunise.

"I'm really worried we're going to see babies who contract this nasty bug because they haven't completed the three shots.

Vaccination programme communications coordinator Kevin O'Connor said breakthrough cases were always expected - and were more inevitable as the proportion of people vaccinated rises. He said the MeNZB vaccination was 75-80 per cent effective.

"If you get 80 per cent of under-fives around the country to have three doses, then you can expect that a proportion of those will not be fully protected."

He noted that of the 10 cases highlighted, the majority suffered mild effects from the disease. Two were admitted to intensive care, the rest had to be hospitalised.

The baby who developed the disease required hospitalisation but did not need intensive care. All patients have made a full recovery.

More than 2.8 million doses have now been administered - more than 1 million people have had at least one dose and more than 890,000 people have had all three doses.

It takes up to 28 days after the last dose for a person to be fully immunised and protected.

National meningococcal vaccine strategy director Dr Jane O'Hallahan said the extra vaccine was only being considered for infants because they were the most vulnerable to the disease.

"We know that infants generally respond to a lesser extent to immunisations in the first year of life than older children and therefore it was likely that a fourth dose may be required to boost their level of immunity and give them longer protection."

Of the nine other patients who contracted the virus, seven were over five years old and two were under five.

Dr O'Hallahan said the fourth shot was not being considered for patients older than infant age because of the relatively small number who had contracted the illness.

"I think the vaccine is showing itself to be effective. The vaccine is having a good impact on the epidemic, however we've always been concerned around the infants who have immature immune systems ... and require an additional dose to give them the level of protection that older children have gained."

She said the ministry would not be recommending a fourth vaccination shot for any age groups other than infants, because "there was no suggestion that it was warranted at this stage".

She said if people requested a further shot from their doctor, they could get it.

But there was no evidence that a fourth vaccination would have helped the nine older patients who contracted the disease, Dr O'Hallahan said.

- Additonal reporting NZPA