Even as the medical community debates the widespread use of Gardasil, a vaccine that helps prevent cervical cancer, the government has made it a mandatory treatment for young women seeking to immigrate to the U.S.

The policy, which went into effect Aug. 1, has angered some immigrant advocates, who say that forcing foreigners to take the costly vaccine saddles them with an unfair financial burden. The decision has also upset health policy experts in the U.S., who see the requirement as excessive.

The addition of Gardasil as a mandatory vaccine is the result of a 1996 immigration law, which states that any vaccination recommended by the U.S. government for its citizens becomes a must for green-card applicants. After the immunization committee of the Centers for Disease Control and Prevention advised last year that Gardasil be given to females ages 11 to 26 in the U.S., the recommendation became an automatic requirement for prospective immigrants when the government updated its list of vaccines in July.

However, even some of the CDC physicians and experts who promoted Gardasil in the U.S. say they never intended to make the vaccine mandatory for young female immigrants.

"If we had known about it, we would have said it's not a good idea," said Jon Abramson, who was chairman of the CDC's Advisory Committee for Immunization Practices when the body recommended the vaccine for U.S. citizens last year.

"We don't want someone coming into the U.S. who hasn't been vaccinated against measles or chickenpox," said Dr. Abramson, who is currently chairman of the department of pediatrics at Wake Forest University School of Medicine in Winston-Salem, N.C. "HPV can only be communicated by sexual contact....This is not something that endangers kids in a school setting or puts your population at risk."

A spokeswoman for U.S. Citizenship and Immigration Services said the requirement for the cervical-cancer vaccine, along with other mandated vaccines, reflects "a statutory requirement. It's based on CDC recommendations."

A CDC spokesman said the experts on the immunization committee didn't realize their decision would affect tens of thousands of immigrants. However, a government official said the cervical vaccine's inclusion on the list might be reviewed.

Gardasil is hailed by many as a breakthrough drug because it can prevent infection by four strains of human papillomavirus, including two believed to cause 70% of all cervical-cancer cases. The viruses are transmitted through sexual contact. The vaccine, which is produced by Merck & Co., won Food and Drug Administration approval in 2006 for females ages 9 to 26, and since then some public-health policy makers have argued that for young women, Gardasil should be included alongside the standard regime of commonly administered vaccines, such as mumps and meningitis.

In the U.S., nearly 4,000 deaths are caused by cervical cancer each year. In September, the FDA also approved Gardasil for the prevention of cancers of the vagina and vulva.

Still, some studies and experts have raised questions about its effectiveness and safety, as well as whether its blanket use among girls is necessary. They say that even if women get the pricey vaccine, they need to continue having an annual Pap screening since they could contract HPV strains the vaccine doesn't fight.

A study published in August in the New England Journal of Medicine suggested the vaccine may not be cost-effective for older females who may have already been exposed to HPV in their lifetime. An earlier study found that adverse effects, such as seizures, could occur.

"Given the controversy over the vaccine's effectiveness and adverse side effects, mandating the vaccine for immigrant women is premature and is arguably equivalent to using them as test subjects," said Priscilla Huang, policy and program director at the National Asian Pacific American Women's Forum.

Foreigners in the U.S. or abroad who apply for permanent residency must visit a U.S.- approved physician or clinic to get vaccines and undergo tests in order to receive health clearance. Of the 14 required vaccines, 13 are designed to combat infectious diseases that are transmitted by respiratory route and are considered highly contagious. Gardasil is the sole exception. The three-dose regimen of Gardasil costs $360, making it one of the priciest vaccines on the market; one dose is required of female immigrants ages 11 to 26.

Most critics of the government mandate say they aren't playing down the benefits of the vaccine. However, some note that green-card applicants already are paying application fees that can cost more than $500, as well as shouldering the cost of other vaccines. Adding a dose of Gardasil at about $120 to the mix "is outrageous; it's creating an economic barrier," said Tuyet Duong, a senior staff attorney at the Asian American Justice Center, a national advocacy organization in Washington.

The drug has been a top seller for Merck, generating more than $1 billion in revenue. However, a Merck spokeswoman said in a statement, "We were not aware of the policy and we did not lobby for this provision in any way." She added that the pharmaceutical giant wouldn't engage in any efforts to address implementation of the requirement.