Transcript
Auckland University's Helen Petousis-Harris says there are three things that kill people after receiving vaccines.
Dr Petousis-Harris says the babies in Samoa did not have an allergic anaphylactic reaction, and she says it's unlikely that the vaccine became contaminated as the process was too quick.
"Looking at how quickly the deaths occurred really leaves only one real possibility and that is that something other than water was used in the vaccine but those investigations are what's being carried out now to see what actually happened."
Two investigations are underway, one by health authorities, the other by police.
New Zealand's director of protection, regulation and assurance at the Ministry of Health says the vaccines Samoa receives are of high quality, made in quality environments and distributed appropriately.
Dr Stewart Jessamine says across the Pacific, the Caribbean and South America there have been no other issues with the same batch of vaccine.
"So this is looking at something that's come to light in Samoa. Same time, also we understand the same vial. Samoa uses a five dose vial and we understand that the both children received the dose from the one vial."
Samoa's attorney general Lemalu Hermann Retzlaff says police are investigating whether there is sufficient evidence to bring criminal charges against the medical staff involved.
"The police investigation's at the point now where we are looking at the evidence that's been collected and we've asked New Zealand for assistance on testing and we're going to continue our investigations particularly around the staff that were involved in all aspects of the vaccinations."
Police in Samoa are awaiting the results from laboratory tests being conducted in New Zealand.
Lemalu says all vaccinations have been stopped while the deaths are being investigated.
"I mean the tragedy for these two children is that it's actually led us to the point where it's become a public safety issue for all of our children. And we're currently in the position where there's no immunisation right now until we sort out what we've got to do. So we're taking this very seriously, it's actually a priority right now for us in law enforcement and in government."
Our correspondent in Samoa Autagavaia Tipi Autagavaia says parents are concerned for the safety of their children because they can't currently get them vaccinated.
"People are now willing to find out the outcome of the investigation, especially the analysis from overseas."
Dr Stewart Jessamine says while the loss of the two babies is a tragedy, it's important that the vaccinations are resumed so as to avoid any deaths from measles.
He says all viral infections can lead to severe side effects and the only protection against them is vaccination.