U.S. Rep. Anna Eshoo is seeking a way for the federal government to pay for additional COVID-19 tests for those on Medicare after the Biden administration ramped up supplies this week.

"Without comparable benefits available through Medicare, more than 18% of our nation's population will be made to pay out-of-pocket for additional at-home COVID-19 tests" Eshoo, D-Palo Alto, wrote in a letter to Xavier Becerra, Health and Human Services secretary. "Americans enrolled in Medicare are among the most susceptible and vulnerable to infection."

This week, the Biden administration began supplying up to four at-home COVID tests to American households, a significant step toward expanding access to rapid testing. But an even larger increase in free testing availability that offers up to eight additional tests per month to those with private insurance likely leaves out those most-at risk of death and severe illness from contracting COVID-19. The gap in the legislation Eshoo pointed out requires private insurers but not Medicare to cover the additional tests. Medicare covers 64 million people who are either 65 and older or have long-term disabilities.

According to the CDC, people 65 and older have made up nearly three-quarters of all COVID deaths. Eshoo's letter states that Medicare beneficiaries are currently covered for just one lab test per year with a health care professional's recommendation.

Free testing sites offered by county or other local governments, including those in San Mateo County, often rely on lab results that can take multiple days to be received. Additionally, access can be spotty and availability hard to track.

Eshoo pointed to broadening testing access as a "critical component" of the nation's strategy to mitigate the virus's spread, and urged the federal government to expand coverage to Medicare beneficiaries.

"Experts have identified that rapid at-home tests are a critically important public health intervention. The comfort and convenience of these tests in one's own home can help people better manage their risks and quickly take action to prevent further spread," her letter states.