Each year on Dec. 1, World AIDS Day is commemorated around the globe. It celebrates progress made in the battle against the disease and brings into focus the challenges that remain. World AIDS Day 2004 centers on women and girls and their struggle against HIV/AIDS.

This year, Catholic Relief Services (CRS) will celebrate the strengths and contributions that women and girls make to protect their families and communities from this disease, while recognizing their increased vulnerability and unequal share of hardships.

Women are biologically, economically and socially more vulnerable to HIV infection than men, with studies showing they can be up to 2.5 times more likely to be infected. While most low-prevalence countries have higher rates in men, the fact is that women now make up about half the people living with HIV/AIDS. In some regions of Africa, women are infected at three to five times the rate of men in the same age bracket.

Lack of economic power and limited access to education can make women almost totally dependent on men and compromise their ability to control their lives and their bodies. And yet despite these disadvantages, women have a unique and valuable role to play in fighting HIV/AIDS. Women are the social capital within families and communities: They shoulder the responsibility of caring for the sick and raising children; they hold families and communities together; and they are a source of leadership and strength in the areas of prevention, care and support.

The United Nations estimates that up to 90 percent of basic care in the developing world is provided in the home by women and girls. They take on this role with no training, without pay and in addition to the work they already perform maintaining the household-cooking, fetching water, working in the field and caring for children and the elderly. Caring for a person with HIV/AIDS can add hours of work to a day that is already full. And of course, when women are the ones infected, the support system runs the risk of completely breaking down.

Women throughout the developing world already work continuously to care for their families. As a result, the sacrifices they make to do so can have far reaching consequences. Caring for the sick can prevent them from earning a living outside the home or tending to their crops, further increasing the family's vulnerability to poverty.

Additionally, girls are more likely than boys to drop out of school to help care for sick family members, find intermittent work or look after younger siblings. This threatens the basic education of girls and women, again making them more vulnerable to poverty and putting them at a higher risk of HIV infection.

But around the world, women are taking leadership roles in the fight against HIV/AIDS. Many are coming forward to tell their personal stories about the disease, despite the threat of social stigma and discrimination. They are learning more about their rights, advocating for equal access to care and treatment and fighting to keep their daughters in school. In Uganda-the only country in the world to dramatically reduce the rate of infections in a generalized HIV/AIDS epidemic-women and young girls are credited with having contributed to the national behavior changes that turned around the epidemiological rising rates of HIV infection.

Women and girls have shown great resilience in the battle against HIV/AIDS, but they cannot continue to bear this responsibility alone. This week, the world has the opportunity to learn more about the vulnerability of women and girls to HIV/AIDS and their role in the fight against it. Indeed, all of humanity is challenged to reflect on the way that HIV/AIDS affects us and how we can respond to the pandemic.

Ken Hackett is president of Catholic Relief Services, the official overseas relief and development agency of the U.S. Catholic community. CRS initiated its first HIV/AIDS program in 1989 and now operates more than 100 projects in 44 countries in the Africa, Asia and Latin America. This year alone, CRS will help more than 2 million people affected by the disease.