(CNN) The Samoan government has launched an inquiry into the deaths of two one-year-old infants after a routine vaccination.
The babies were brought to Safotu Hospital in Savai'i on Friday, where they died within minutes of the receiving the MMR vaccine, Television New Zealand reported.
Samoan Prime Minister Tuilaepa Sailele Malielegaoi expressed his condolences to the families on Monday.
"I have called a full inquiry into the circumstances leading up to this devastating incident which I do not take lightly," he said.
"There are already processes that will determine if negligence is a factor. And if so, rest assured those processes will be implemented to the letter to ensure that such a tragedy will not be repeated and those responsible will be made to answer."
Leausa Take Naseri, director general of health, said he has halted the vaccination program until the inquiry's completion. He has also requested a forensic autopsy on the two babies, as the deaths are also being investigated by police.
Hospital staff involved have also been removed for their own safety, Radio New Zealand reported.
"We're also concerned for the safety of our workers especially the nurses who were involved because it's now easily blamed -- the finger is pointed towards the nurses," Naseri said.
Vaccines prevent almost 6 million deaths worldwide every year, according to the World Health Organization. In countries that widely use vaccines, diseases such as measles have been nearly eradicated, with a 99% reduction in cases.
Typically given in two doses in early childhood, the MMR vaccine protects against three diseases: measles, mumps, and rubella.
One dose is about 93% effective at preventing measles if the person is exposed to the virus, while two doses are about 97% effective, according to the US Centers for Disease Control and Prevention (CDC).
"Most children in the world receive this vaccine or similar vaccines to this," Helen Petousis-Harris, a vaccinologist at the University of Auckland, told CNN. "We have safety data on the vaccine, we understand the effects really well. This type of case is exceedingly rare."
Furthermore, she said, child mortality has gone down in many countries that use these vaccines.
"Every country has a vaccine program that has been demonstrated to be very safe," she added. "At the moment we need to understand what's happened so we can work out strategies to ensure it doesn't happened again. There's a lot we don't know about (the deaths)."