Since late January, the CDC has rushed to distribute the kits to allow states to do their own, faster testing rather than ship all samples to CDC headquarters in Atlanta.
"Obviously, a state wouldn't want to be doing this test and using it to make clinical decisions if it isn't working as well, as perfectly, at the state as it is at CDC", said Dr. Nancy Messonnier, director of the National Center for Immunization and Respiratory Diseases (NCIRD), said at a news conference.
It was not immediately clear how many kits were flawed.
Officials are seeing "fewer and fewer travelers from China, especially from Hubei province", which includes Wuhan, Messonnier said.More news: Mel Tucker lays out his blueprint for Michigan State
As a result, the CDC is remaking parts of the test kits after some produced inconclusive test results. "CDC stands ready to send staff to the affected areas in China to work on this investigation".
She said the C.D.C. was working closely with the states, and would send out new ingredients to laboratories that have encountered the problem.
"We really felt the need for these basic things to be addressed", Jacob Wilson, who is being held at the airbase, told KNSD, "and we hope that the petition would at least be able to address these basic concerns". The flight arrived at Marine Corps Air Station Miramar on February 7.More news: Trump overwhelmingly wins Republican primary in New Hampshire
The CDC on Tuesday released 195 people from quarantine at March Air Reserve Base in California after holding them there for 14 days.
Covid-19 continues its relentless spread throughout China.
The new numbers will likely change health officials' approaches.
Since Chinese authorities first identified the virus in 44 people in December, it has spread to 25 countries and infected 45,171 people, according to the World Health Organization's (WHO) Wednesday report. It has recorded 60,063 confirmed cases and says 5,680 persons have recovered from the coronavirus. There have only been two deaths reported outside of China: one in the Philippines and one in Japan.More news: Year-old Faye Marie Swetlik disappears from SC bus stop