Prof David Murdoch, an infectious disease specialist at Otago's Christchurch campus, said New Zealanders had played key roles in a global study pinpointing the deadliest forms of viruses and bacteria.
The researchers had also identified one vaccine that could save the lives of hundreds of thousands of babies and young children.
The study had highlighted key causes of childhood pneumonia, including respiratory syncytial virus (RSV), which was a major cause of respiratory illness in young children, Prof Murdoch said.
"That will really push on the effort to get a vaccine for RSV treatment.
"That in particular is a game-changer," he said.
Many different bacteria and viruses contributed to the common pneumonia that caused the death of many babies and children in developing countries.
However, in the study, spanning seven countries including Thailand, Bangladesh, South Africa and Kenya, the researchers found one virus, RSV, was present in more than a quarter of all cases.
Findings from the decade-long global Pneumonia Etiology Research for Child Health (Perch) study are published in the latest edition of The Lancet.
Prof Murdoch led the establishment of laboratories in seven countries involved in the study.
The Perch team, funded by the Bill and Melinda Gates Foundation, set up laboratories in the seven countries, in Asia and Africa.
They did a wide range of tests on children hospitalised with severe pneumonia to pinpoint the specific viruses and bacteria involved.
Pneumonia kills more under-5s worldwide than any other disease.
Almost 1 million children globally died from it in 2015.
Prof Murdoch said the Perch study gave direction on where to put resources and a scientific basis for vaccination programmes in countries with the greatest burden of childhood pneumonia.
"Before Perch, we were reliant on old data from the 1980s."
The updated research now gave individual nations, and global agencies such as the World Health Organisation, a clear battle plan to combat pneumonia, he said.
