Q&A: Lower respiratory infections remain one of the world’s most persistent health threats

Lower respiratory infections (LRI) caused 2.5 million deaths and nearly 100 million disability-adjusted life years in 2023. According to new research published in The Lancet Infectious Diseases, the burden of LRI is concentrated on two groups: children under 5 and adults aged 70 years and older — they are experiencing the highest mortality rates.​ This Q&A video with IHME Researcher Sarah Sirota provides insights into this study.

Read the research

Transcript

This transcript has been lightly edited for clarity.

Why is it important to study lower respiratory infections?

Lower respiratory infections were the fourth-leading cause of death and the leading infectious cause of deaths worldwide in 2023. They disproportionately affect both children under 5 years old and adults over the age of 70. And so, for this study in particular, we wanted to assess progress toward the World Health Organization’s Global Action Plan for the Prevention and Control of Pneumonia and Diarrhea, which I’ll just be calling GAPPD, which measures the progress toward reducing deaths from both pneumonia and diarrhea in children under the age of 5.

We focus specifically on the target for pneumonia mortality in this particular study. We also have some newly estimated pathogens that have not been produced by the GBD before. And these pathogens are pathogens that are responsible for lower respiratory infections, and they will help us get a better understanding of the infectious landscape. When we add more pathogens to our analyses, we can better recommend which pathogens end up needing the most attention.

What were the key findings of the study?

As a preface, the GAPPD target is roughly less than 60 deaths per 100,000 children under 5 years old by the year 2025. And we found that though progress has been made since 2010, we aren’t quite at that target yet. In 2023, globally, children had an under-5 mortality rate of 94.8 per 100,000. So not quite at that 60 deaths per 100,000 yet. 

This is a map that shows us the mortality rates per 100,000. Specifically, this is showing children under the age of 5.

Any country here that is shown in blue is a country that has met the GAPPD goal of under 60 per 100,000 deaths in children under 5. Countries that are shown in green are getting closer to that goal. Yellow countries are further away from the goal, and orange and red countries are furthest from the goal.

We also found that the pathogen Streptococcus pneumoniae continues to be responsible for the highest number of lower respiratory infection deaths. And this trend has been pretty consistent since the 1990s. Another key finding was that these newly modeled pathogens that we covered in this study accounted for around 22% of the total lower respiratory infection deaths globally.

What gender, geographical, and age differences did the study reveal?

We see the highest rates of deaths and incidence in adults over the age of 70 and children under the age of 5. 

This figure is showing deaths on the left and mortality rate per 100,000 on the right. Two years are shown here. The green bars correspond to 2010, while the blue bars are representing 2023. On the x-axis, we can see multiple different age groups that we’ve chosen to show in our analyses.

The right bar chart gives us a clear picture of the mortality rate burden being heaviest on adults over 70 and children under 5 in both 2010 and 2023.

We also see that men tend to have a higher mortality rate than women from lower respiratory infections. 

In this figure, we are looking at the trends of deaths on the left and mortality rates on the right for men, which is the red line, women, the blue line, and both sexes combined, which is the green line. The trends that we’ve shown here are spanning from 1990 up to 2023.

Here you can see in the figure on the right that men tend to have higher mortality rates from lower respiratory infections than women. 

And when we’re looking across different locations, we found that 129 of the 204 locations that the GBD models, 129 of them were meeting the GAPPD target of less than 60 deaths per 100,000 children under 5 in 2023.

When we take a look at which locations are not quite meeting that GAPPD goal, we see that sub-Saharan Africa is the furthest from that target. And this can be due to a lot of different factors. It could be due to access to health care, access to vaccinations, even down to different sanitation practices or standards in different countries.

What are the challenges to reducing LRI burden, and how can this be achieved?

Lower respiratory infections continue to be a leading cause of deaths, especially in children under 5 and adults over 70. Reducing lower respiratory infections will require continuous investment in vaccine development and access, especially in high-burden populations and locations. It’s also vital that we continue enhancing surveillance and data sharing, so that public health officials can make informed decisions about the current landscape of lower respiratory infections.

We also know that antimicrobial resistance plays a large role in the landscape of pathogens and can drastically change how deadly these diseases can become and which pathogens are more apt to cause deaths. Because of this, it’s important that we continue supporting antimicrobial stewardship programs.