Photo: Allen J. Schaben/Los Angeles Times via Getty Images

A 25-year-old man in Nevada has been identified as the first person in the U.S. to get COVID-19 twice, according to a study published in the medical journal The Lancet on Monday.

Why it matters: The finding indicates that being infected with the virus "might not guarantee total immunity in all cases," the study's researchers write. It also calls into question the value of any potential source or indicator of immunity — whether that's antibody testing, the use of blood plasma as a treatment, or perhaps even a vaccine, per Axios' Sam Baker.

  • People who have been infected "should take identical precautions" as those who have never had it, the researchers write.

The big picture: The Nevada case is the fifth confirmed reinfection worldwide since scientists documented the first reinfection in Hong Kong in August, per NPR.

Worth noting: The Nevada patient first tested positive on April 18, and again on June 5. He tested negative twice in between the cases, according to the study.

  • His symptoms were more severe during the second infection.

The bottom line: The finding could have significant implications regarding the efficacy of a potential coronavirus vaccine, which "might not result in a level of immunity that is 100% protective for all individuals," the researchers wrote.

Read the full study, via DocumentCloud:

Go deeper

The pandemic is getting worse again

Expand chart
Data: The COVID Tracking Project, state health departments; Note: Due to a database error, Missouri had a 3 day gap in reporting from Oct. 11-13; Map: Andrew Witherspoon/Axios

Every available piece of data proves it: The coronavirus pandemic is getting worse again, all across America.

The big picture: As the death toll ticks past 212,000, at a moment when containing the virus ought to be easier and more urgent than ever, we are instead giving it a bigger foothold to grow from.

Updated 10 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Aïda Amer/Axios

  1. Politics: Chris Christie: Wear a mask "or you may regret it — as I did" — Senate Democrats block vote on McConnell's targeted relief bill.
  2. Business: New state unemployment filings fall.
  3. Economy: Why the stimulus delay isn't a crisis (yet).
  4. Health: FDA approves Gilead's remdesivir as a coronavirus treatment How the pandemic might endMany U.S. deaths were avoidable.
  5. Education: Boston and Chicago send students back home for online learning.
  6. World: Spain and France exceed 1 million cases.
13 hours ago - Health

FDA approves Gilead's remdesivir as a coronavirus treatment

A production line of Remdesivir. Photo: Fadel Dawood/picture alliance via Getty Images

Gilead Sciences on Thursday received approval from the Food and Drug Administration for remdesivir, an antiviral treatment that has shown modest results against treating COVID-19.

Why it matters: It's the first and only fully FDA-approved drug in the U.S. for treating the coronavirus.