NZ experts in landmark childhood pneumonia study
A major new study has refocused the global fight against childhood pneumonia – and New Zealand researchers played a key role.
Globally, pneumonia causes more deaths among children under five years old than malaria, tuberculosis, HIV, Zika virus, and Ebola virus combined – about 900,000 fatalities, with more than 100 million reported cases each year.
The Pneumonia Etiology Research for Child Health (PERCH) study involved seven countries and nearly 10,000 children. It revealed viruses as the new leading cause of global childhood pneumonia. Published in the prestigious journal The Lancet, the findings will impact how we prevent, diagnose and treat this illness in the 21stcentury.
In particular, they bring a new urgency to the hunt for a vaccine for the virus that accounted for almost a third of all cases.
Amongst a tight leadership team, New Zealanders played key roles. Associate Professor Stephen Howie at the University of Auckland was country lead for The Gambia study arm, while Professor David Murdoch at the University of Otago, Christchurch, led the laboratory arm of PERCH.
Dr Howie is an associate professor in the University of Auckland’s School of Medicine and a paediatrician at Waitemata DHB. “It is exciting that these important results are now being released: we believe they will help accelerate progress preventing deaths from pneumonia, and so contribute to children surviving and thriving globally,” he says.
“Pneumonia is a leading cause of illness and death worldwide, including in New Zealand and the Pacific region, and I am delighted that Kiwi researchers from the University of Auckland and University of Otago are a part of this landmark study.”
Aotearoa New Zealand has high rates of childhood pneumonia, two to five times higher than Australia, England and the UK. Ten percent of under-two year olds get hospitalised for respiratory infections in New Zealand, and our rates of pneumonia, and of death from pneumonia, are highest amongst our Māori and Pacific children, and children in poverty. A total of 122 children died of the illness in the 10 years to 2015.
Dr Howie: "We have much higher rates of pneumonia than we should. Poverty, overcrowding, smoking, poor nutrition, low immunisation rates, and problems getting the treatment kids need are key factors in these high rates.
"And it is not just with pneumonia that we see this but a whole range of diseases. I spent over a decade working in West Africa, and my training in New Zealand was a much better preparation for what I faced there than it ever should have been. So we need to face up to these things in our own backyard. While we do that, we also need to look outwards to what is happening in the world."
PERCH was led by the International Vaccine Access Center in the renowned Baltimore-based Johns Hopkins Bloomberg School of Public Health, and involved more than a dozen institutions and programmes. It is the largest and most comprehensive study of its kind since the 1980s.
Explains Dr Howie, “There used to be a strong divide between developed countries and low-and middle-income countries: bacterial causes predominated in low and middle-income countries, while viral causes were more common in developed countries. The PERCH study revealed a shift to viral causes dominating worldwide.”
This is due in part to successful roll-outs of vaccines against H. influenzae type b and S. pneumoniae, two important bacterial causes of pneumonia.
In the study, children who had been hospitalised with severe pneumonia were tested for viruses, bacteria and fungi. Results showed that two-thirds (61 percent) of all cases were caused by viruses, and a particular virus – known as the Respiratory Syncytial Virus (RSV) - accounted for nearly one third (31 percent).
Other top causes were rhinovirus, human metapneumovirus, parainfluenza viruses, and the bacteria Streptococcus pneumoniae, Haemophilus influenzae, tuberculosis, and Staphylococcus aureus. Among the severest cases in the study, bacterial causes remained very important.
“Immunisation is a vital protection against infections, including many bacteria and viruses that cause pneumonia, and we need to make sure children get the full benefit of existing vaccines, as well as developing new ones, such as an RSV vaccine,” says Dr Howie.
PERCH also developed a new, high-powered statistical tool to better understand the causes of infection in children. The hope is that tools could help doctors more accurately identify what has caused pneumonia for an individual child, enabling better and smarter treatment of children with severe pneumonia, and reduce unnecessary antibiotic use leading to antibiotic resistance.
The study ran in Bangladesh, The Gambia, Kenya, Mali, South Africa, Thailand, and Zambia.
"The vast majority of pneumonia deaths are completely preventable," says Dr Howie. "All of those children around the world are ‘our children’ too. Just as we cannot be comfortable with kiwi kids suffering, we cannot be comfortable with children in our region and all around the world suffering either.
"It is a wonderful thing that kiwi doctors have been so involved in a study like PERCH. I want to encourage kiwis to get more and more involved in grappling with pressing health needs around the world. We have a lot to offer."