Jayne O'Donnell

USA TODAY

Medicaid can be used to cover mosquito repellent to prevent the spread of the Zika virus, federal regulators told state and private Medicaid officials in a letter sent Wednesday.

Coverage of repellent — when prescribed by a health professional — with the federal matching dollars given other Medicaid-covered treatments is the primary change in the new Department of Health and Human Services guidance. The letter is intended to clarify how low-income people covered by Medicaid can protect themselves so they don't contract the virus or get tested and treated in case they do. HHS alerted about 50,000 people involved in Medicaid plans.

The Centers for Disease Control and Prevention says Zika is the definitive cause of an epidemic of birth defects in Brazil and other some countries with outbreaks of the virus. It also causes Guillain-Barré syndrome, a rare condition in which the body attacks its own nerve cells, causing paralysis. The virus is largely spread by mosquitoes, can sometimes be transmitted sexually or through blood transfusions.

The $1.9 billion President Obama requested from Congress in February to combat Zika included a provision to boost Puerto Rico's Medicaid program by $250 million for a year, but Congress has so far only approved a much smaller amount. Puerto Rico has been hard hit by both Zika and a financial crisis that has left the territory unable to cover the cost of testing and treating residents.

Although the only U.S. residents with Zika got it while travelling abroad, experts expect people here may become afflicted by the virus as early as this summer.

But there may be far bigger problems when it comes to Zika and health coverage, says Joan Alker, executive director of the Georgetown University Health Policy Institute. Even pregnant women in the United States legally often have to wait five years before they get Medicaid coverage. Only 23 states have accepted the federal offer of matching funds if they cover them sooner. Texas, Florida and Arizona — which face some of the greatest threats from the virus — have not.

And undocumented immigrants have no health coverage at this time.

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The letter sent by Vikki Wachino, director of HHS' Center for Medicaid and CHIP Services, also reminded Medicaid managed care plans that they can go beyond the required services that must by covered by Medicaid to do more to stop the spread of Zika. As Alker notes, the lifetime health care for a child with microcephaly, a condition in which babies are born with unusually small heads and incomplete brain development, is "very, very costly" so the plans might pay to have screens installed to keep mosquitoes out of homes.

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States can also make optional diagnostic and screening Medicaid services available to adults concerned about Zika. And, HHS noted, they are required to cover all medically necessary diagnostic services related to the detection of a Zika virus infection, including diagnosis of microcephaly and other birth defects without limit to individuals under the age of 21.