"weak health" is correct and usable in written English.
You can use it to refer to someone's physical state, e.g. "She was born with weak health, so she had to go to the hospital regularly for checkups."
However, all too often low-income countries are poorly resourced and have weak health systems.
However, access to clinical care is limited in resource-poor settings with weak health systems.
He fears a similar outbreak in another country with weak health systems could result in the same inaction.
The area has long suffered from government indifference, resulting in weak health and education services and infrastructure.
Yet, further progress has been hampered by weak health systems, poverty and multi-resistant strains of TB.
The report recognized that preventing and treating AIDS was a complex problem hampered by weak health systems in poor countries.
In the eastern Mediterranean region, weak health systems and conflict and population displacement have hampered vaccination efforts, says WHO.
Weak health systems in West Africa helped create the conditions that allowed Ebola to emerge and spread.
"Weak health systems are no justification for inaction," said Merlin's director of health and policy, Linda Doull.
And increasing urbanization worldwide, alongside weak health systems, means vulnerable people are living on top of one another.
Needless to say, doing so is very challenging and very expensive, especially in highly urbanized areas, with weak health systems.
