More than 600,000 girls in Tanzania have started receiving vaccines to prevent cervical cancer.
Girls aged between nine and 14 are being targeted to protect them from developing the illness at an early age.
"Prevention is better than cure, elongating lives and and reducing treatment costs," said Dr Daphrosa Lyimo, heading the government rollout.
Cervical cancer is the most common cancer in Tanzania and kills more women than any other form of the illness.
Tanzania is the seventh African country to introduce the human papilloma virus (HPV) vaccine into its routine immunisation programme, after Uganda, Rwanda, Botswana, Mauritius, Seychelles and South Africa.
The health minister says $15 (£11) will be spent treating each girl.
What is cervical cancer?
Cervical cancer is a cancer that develops in a woman's cervix - the entrance to the womb from the vagina.
It is one of more than 100 types of human papilloma virus (HPV), of which at least 13 are cancer-causing. Cervical cancer is caused by sexually acquired infection with certain types of HPV.
Risk factors include early first sexual intercourse, multiple sexual partners and tobacco use, and immune suppression (such as in HIV-infected individuals).
Symptoms can include:
- irregular bleeding between periods or abnormal vaginal bleeding after sexual intercourse
- back, leg or pelvic pain
- fatigue, weight loss, loss of appetite
- vaginal discomfort or odourous discharge
- a single swollen leg.
Screening for the virus is recommended to detect it at an earlier stage. HPV vaccines are another preventative measure. Treatment for patients with cervical cancer depends on far the cancer has spread, but can include surgery to remove some or all of the womb, radiotherapy and chemotherapy.
Source: World Health Organization
Tanzania's government hopes the early-stage vaccines will help reduce the bill for cervical cancer treatment, which typically costs about $2,000 (£1,410) per patient.
Low-cost doses of the HPV vaccine are being supplied to Tanzania by the Vaccine Alliance, Gavi.
Poor countries are disproportionately affected by cervical cancer. According to Gavi, the five worst-affected countries are in Africa - Malawi, Mozambique, Comoros, Zimbabwe and Zambia.
Globally, more than 260,000 women die of of the illness each year, with low- and middle-income countries accounting for 85% of all deaths.
"The majority of these deaths are preventable, thanks to a safe and effective vaccine," says Gavi CEO Dr Seth Berkley.
"That's why we are working hard to ensure girls across Africa, from Tanzania to Senegal, have access to this lifesaver."