We have four major global challenges in health care. And I think the unsung hero of the health-care system – primary health care – can help us solve them all. The first challenge is the rise of chronic noncommunicable diseases such as hypertension, which is the world’s leading killer. The second challenge is fragmentation of care. Complex systems are unable to integrate care for patients with multiple conditions. We see this when trying to get test results to patients, or during the risky period when patients are discharged from hospital to home. The third challenge we face is the persistence of preventable infectious and chronic diseases. One-third of deaths in the US are preventable, as are up to 80-90% of deaths in low-income countries. That means that most of the 17,000 children under the age of five who die every day could have been saved. That brings us to the fourth challenge: low-quality care. Imagine a woman in Nigeria seeking care for her pneumonia-stricken child. If she can find a clinic, there is a 50% chance that someone will be there when she arrives. If there is, that person correctly diagnoses pneumonia, a leading cause of death, 50% of the time. Even with the right diagnosis, the right treatment is available and will be administered 50% of the time. In other words, the rate of successful treatment rate is about 12%. Seen against in this background, improving primary health care is essential. Primary care is not just about building clinics or implementing disease-specific programs. It is really about five core functions (the 5 Cs).. The first is contact access. Where do I go for the majority of my health needs and when I need something more acutely? The second is continuity. Does someone know me over time? Do they know my allergies so that they don’t give me the wrong antibiotic? The third is coordination. Can someone help navigate across my lifespan and address my multiple health and social needs? The fourth is comprehensiveness. Can I get a range of services, from acute pneumonia care to having my blood pressure controlled, and much more? And, more important, can someone know me as a whole person and not just as a pathology? And that relates to the fifth core function: person-centeredness. Are we able to create trusting relationships over time that help people attain their health goals? We can address today’s four major global health challenges by building effective primary health-care systems. That means building clinics and supply chains while not losing sight of the real goal: creating a reliable source of accessible, competent, and trusted care to promote and maintain health over a lifetime. Asaf Bitton is Director of Primary Health Care at Ariadne Labs, a joint center of Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health. Copyright: Project Syndicate.