Approximately 7.74 million people worldwide are living with sickle cell disease, based on 2021 estimates published in The Lancet Haematology. In the United States, the condition affects an estimated 100,000 people, with life expectancy still more than 20 years shorter than the national average.
Global Numbers at a Glance
Sickle cell disease is the most common inherited blood disorder on the planet. The 7.74 million global estimate comes with a wide range of uncertainty (between 6.5 and 9.2 million), largely because many cases in low-income countries go undiagnosed. Each year, roughly 515,000 babies are born with the condition worldwide. That number is expected to keep climbing: population growth in the regions most affected could push annual newborn cases above 400,000 for sickle cell anemia alone (the most severe form) by 2050, even without accounting for other subtypes.
Where Sickle Cell Disease Is Most Common
The vast majority of people with sickle cell disease live in Sub-Saharan Africa. The WHO estimates it affects about 800 out of every 100,000 people across the African region, and around 1,000 babies are born every day on the continent at high risk for the condition. This concentration exists because carrying one copy of the sickle cell gene (without having the full disease) offers some protection against malaria. Over generations, the gene became far more common in areas where malaria was widespread.
India is the second major hotspot, particularly in tribal and rural communities in central and western states. Significant populations also exist in the Middle East, the Mediterranean, and among diaspora communities in the Americas and Europe.
Sickle Cell Disease in the United States
In the U.S., sickle cell disease disproportionately affects Black Americans. Among non-Hispanic Black newborns, the birth prevalence is about 1 in every 350, according to CDC data from an 11-state surveillance program between 2016 and 2020. The disease also occurs in Hispanic Americans and people with Mediterranean, Middle Eastern, or South Asian ancestry, though at lower rates.
Every state in the U.S. screens newborns for sickle cell disease shortly after birth through a routine heel-prick blood test. This universal screening means nearly all cases are identified within the first few days of life, which allows early treatment and has dramatically reduced childhood deaths compared to earlier decades.
The Carrier Gap
The number of people who carry the sickle cell trait, meaning they have one copy of the altered gene but not the disease itself, far exceeds the number with full sickle cell disease. Globally, tens of millions of people are carriers. In the U.S. alone, estimates range from 1 to 3 million. Carriers typically have no symptoms and may not know their status unless they’ve been tested. However, two carriers who have a child together face a 25 percent chance with each pregnancy that the child will have sickle cell disease.
How the Disease Affects Life Expectancy
Sickle cell disease causes red blood cells to become rigid and crescent-shaped, which blocks small blood vessels and reduces oxygen delivery to tissues. This leads to episodes of severe pain, organ damage over time, increased risk of stroke, and vulnerability to infections. In the United States, people with the condition live an estimated 20-plus years less than the general population. When quality of life is factored in (accounting for years spent managing pain, hospitalizations, and disability), the gap widens to more than 30 years.
In high-income countries, advances in care have shifted sickle cell disease from a childhood illness to a chronic adult condition. Most children diagnosed today in the U.S. survive into adulthood. The picture is starkly different in Sub-Saharan Africa, where limited access to screening, antibiotics, and specialized care means a significant proportion of affected children still die before age five.
Why the Numbers Keep Growing
The global population with sickle cell disease is increasing for two main reasons. First, the regions with the highest prevalence, particularly West and Central Africa, have rapidly growing populations and high birth rates. Second, improvements in care in some African countries mean more children are surviving into adulthood, adding to the total number of people living with the disease at any given time. This combination of more births and better survival is projected to significantly increase the global burden over the coming decades, putting pressure on health systems that are already stretched thin.