WASHINGTON, Dec 2 (Reuters) – U.S. President Joe Biden on Thursday will lay out his strategy to fight the Omicron and Delta coronavirus variants over the winter, including free and insurer-funded at-home COVID-19 testing and new requirements for international travelers.The U.S. government will require private health insurers to reimburse their 150 million customers for 100% of the cost of over-the-counter, at-home COVID-19 tests, administration officials said, and make 50 million more tests available free through rural clinics and health centers for the uninsured.The administration is urging all eligible Americans to get vaccinated or booster shots to fight Omicron, which is spreading quickly around the world, and will increase family vaccination sites and expand availability at pharmacies.Register now for FREE unlimited access to reuters.comRegisterLess than 60% of the total U.S. population, or 196 million people, have been fully vaccinated, one of the lowest rates among wealthy nations. The administration says another 100 million are eligible for boosters. The Centers for Disease Control and Prevention said all vaccinated adults should get a booster in light of waning protection over time and the emergence of Omicron. read more The United States also plans to require inbound international passengers to be tested for COVID-19 within one day of departure, regardless of vaccination status. Mask requirements on airplanes, trains and public transportation vehicles will be extended to March 18. read more The efforts to expand testing and shots come as the world faces new threats from the Omicron variant, and the United States confronts a heavily entrenched, politically fueled anti-vaccination culture.Fears about the variant have pounded financial markets and created doubts about the speed of the global economic recovery as the pandemic rages on.The measures rolled out on Thursday could be further expanded, White House Press Secretary Jen Psaki said.”We are assessing and reviewing, working 24/7…to evaluate, learn more about this variant, and we will assess if additional restrictions need to be put in place,” Psaki said about travel.Requiring insurance companies to pay for tests was something the administration “agreed was implementable and possible to do now and we will continue to build on it,” Psaki added.Biden was announcing the strategy at the National Institutes of Health.INSURERS SEEK CLARITYThe Biden administration will lay out details on whether private health insurance companies will get government money to reimburse customers for over-the-counter tests when it releases guidance on the issue in January, Psaki told reporters.Government agencies including the Health and Human Services Department, Labor Department and Treasury Department will issue guidance on the issue by Jan. 15, the White House said.The administration plans to distribute 50 million tests to rural clinics and testing sites to help cover those who do not have private insurance and those who do not have insurance at all.Additional free tests at health care clinics should be available as soon as this month, Psaki said.The largest U.S. employer-based health insurers include Cigna Corp (CI.N), UnitedHealth Group (UNH.N) and CVS Health (CVS.N). Currently, the insurers are reimbursed a set amount by the government for most medically necessary COVID-19 tests performed in labs and medical offices.Kristine Grow, spokesperson for insurance industry lobby AHIP, said the industry is working with the administration to make sure the impact of any testing plan is fully understood. Areas of concern include price gouging on these tests, higher premiums and clear rules and guidance for implementation, she said.Morningstar analyst Julie Utterback said she views the government’s plan as a shift in the potential site of testing, rather than a significant increase in costs for health insurers, assuming at-home tests can be accepted as valid.”To control the spread of the virus from a policy perspective, I see the logic in trying to keep infected people at home instead of forcing them to interact with people outside their household when they are experiencing symptoms,” Utterback said.Evercore ISI analyst Michael Newshel said the strategy could come at a notable cost for health insurers, with the coverage requirement possibly lasting through the first half of the year.More than 786,000 people have died from COVID-19 in the United States, including 37,000 in November alone.Biden introduced vaccination mandates requiring large companies, federal workers and contractors, and some healthcare personnel to be vaccinated in September.On Nov. 30, courts blocked two of them, potentially affecting millions of workers. read more Biden will press companies to require employees be vaccinated or tested regularly despite legal setbacks, the White House said.”The president will call on businesses to move forward expeditiously with requiring their workers to get vaccinated or tested weekly. This is especially important given the Omicron variant,” the White House said in a statement.Register now for FREE unlimited access to reuters.comRegisterReporting by Jeff Mason; additional reporting by Susan Heavey, Trevor Hunnicutt, Ahmed Aboulenein and Amruta Khandekar; Editing by Shri Navaratnam, Heather Timmons, Lisa Shumaker and Bill BerkrotOur Standards: The Thomson Reuters Trust Principles.