Concerns New Zealand's vaccination rate for whooping cough is trailing behind other countries

Three infants, all under the age of one, have died from the disease since February.

Greater levels of protection can be passed on to babies if a mother is vaccinated during her second term of pregnancy.

But vaccinologist Helen Petousis Harris says the health system has been strained and there's no light at the end of the tunnel.

She says there aren't enough resources getting through to health services, meaning the message might be getting lost.