Not enough young children in Samoa are being vaccinated against measles, the country's top health official is warning.
Children under the age of four make up all but four of the 33 deaths in Samoa's escalating measles epidemic.
The age group has been made a priority under a mass vaccination campaign and 1419 have been immunised in two weeks.
However, Samoa's Director General of Health, Leausa Dr Take Naseri, said more children needed to be reached.
"We are still not satisfied with the coverage of the six months to the four years. We still haven't crossed 40 percent of that age group.
"The other age groups are doing steadily, but we are still worried that most of the kids are not coming forward or not being brought by their parents."
Leausa said when children were brought in for treatment, their condition was too severe to save them, because they were often presented five to six days after onset of symptoms.
"So they [are] really presented late to the hospital and associated complications are quite high and most have resulted in death."
Asked at a press conference on Wednesday whether the measles epidemic would worsen, Leausa said: "I don't think it has reached its peak."