CDC director Robert Redfield briefs reporters on April 8. Photo: Mandel Ngan/AFP via Getty Images

Coronavirus antibody tests are still relatively unreliable, and it's unclear if people who get the virus are immune to getting it again, the Centers for Disease Control and Prevention cautioned on Tuesday.

What they're saying: The agency explicitly warned against using antibody tests to determine whether someone should return to work or to group people within schools or prisons.

  • Although some evidence suggests that previously having the coronavirus could create "short-term immunity," it is still ultimately unknown whether having COVID-19 antibodies offers protection from the virus, the agency said.
  • Social distancing and face masks are still essential and should not be avoided based on whether you have coronavirus antibodies. More data would be needed for those changes, the agency says.

Between the lines, via Axios' Caitlin Owens: The CDC's updated guidelines point out that even effective antibody tests are likely to have high false positive rates, since not many people have tested positive for the coronavirus.

The big picture: The CDC's caution comes after it confirmed last week that it had been combining the results of diagnostic and antibody coronavirus tests. This distorts data on how widespread the virus is, which is one of the primary uses of antibody tests.

  • It also follows a warning from the American Medical Association that antibody tests that identify those who have previously contracted the coronavirus should not be used to determine immunity.

Go deeper: FDA blocks sale of 29 coronavirus antibody tests in the U.S.

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Updated Oct 7, 2020 - Health

World coronavirus updates

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Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Axios Visuals

New Zealand now has active no coronavirus cases in the community after the final six people linked to the Auckland cluster recovered, the country's Health Ministry confirmed in an email Wednesday.

The big picture: The country's second outbreak won't officially be declared closed until there have been "no new cases for two incubation periods," the ministry said. Auckland will join the rest of NZ in enjoying no domestic restrictions from late Wednesday, Prime Minister Jacinda Ardern said, declaring that NZ had "beat the virus again."

Updated 3 mins ago - Politics & Policy

Coronavirus dashboard

Illustration: Aïda Amer/Axios

  1. Politics: Pence chief of staff Marc Short tests positive for coronavirus — COVID-19 looms over White House Halloween celebrations
  2. Health: Fauci says maybe we should mandate masks if people don't wear them — America was sick well before it ever got COVID-19
  3. World: Polish President Andrzej Duda tests positive for COVID-19.

Colleges drive a new wave of coronavirus hotspots

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Data: The COVID Tracking Project, state health departments; Note: Washington state case count does not include Sept. 1; Map: Andrew Witherspoon, Sara Wise/Axios

America’s brief spurt of progress in containing the coronavirus has stalled out.

Why it matters: We had a nice little run of improvement over the past month or so, but cases are now holding steady at a rate that’s still far too high to consider the outbreak under control.