CDC guidelines and news coverage sow confusion about immunity. [Credit: Nancy R. Gough, BioSerendipty, LLC]

COVID-19 Immunity Not Guaranteed for 3 Months or Limited to 3 Months

CDC guidelines do not mean we know how long COVID-19 immunity lasts.

Lots of confusion out there today. Yesterday, I saw a tweet in the news part of Twitter titled, “CDC says recovered COVID-19 patients will have immunity for about three months.”

Tweet on the news part of Twitter that misrepresents CDC guidelines for testing people who recover from COVID-19.

Newsweek had a similar headline: “Those infected with COVID-19 are immune for just 3 months, CDC says”

Newsweek headline about what CDC guidelines meant about immunity.

Both headlines are misinterpretations of what CDC meant. The CDC did not state that immunity only lasts for 3 months or always lasts for as long as 3 months.

We have no idea how long immunity will last in people who become infected with SARS-CoV-2 and get COVID-19. We do not know if immunity persists for different lengths of time in people who have asymptomatic disease or people who develop and recover from severe disease. The virus has not been in existence long enough to know how long immunity lasts!

The CDC guidance that prompted this news statement on Twitter, also prompted ABC News to make the statement that people who have fully recovered from the virus are protected for 3 months and can interact with others.

Tweet from ABC News that misrepresents CDC guidelines for testing people who recover from COVID-19.

The part of the CDC statement about not developing symptoms again seems to have been lost on the news media. If a person can develop symptoms again, then either he or she was not fully recovered or he or she was re-infected.

People who have recovered from COVID-19 should not consider themselves no risk to themselves or others. They should still practice social distancing and wear a mask or face covering when in close proximity to people outside of their household or germ circle.

We do not have enough information about individual immunity to know who will have sufficient immunity after having COVID-19 to not be infectious to others and who will not become sick if subsequently exposed. There is individual variability in the immune response among the people who have recovered from COVID-19.

CDC has now tried to clarify this misinterpreted information in a press release:

“On August 3, 2020, CDC updated its isolation guidance based on the latest science about COVID-19 showing that people can continue to test positive for up to 3 months after diagnosis and not be infectious to others. Contrary to media reporting today, this science does not imply a person is immune to reinfection with SARS-CoV-2, the virus that causes COVID-19, in the 3 months following infection.”

“The latest data simply suggests that retesting someone in the 3 months following initial infection is not necessary unless that person is exhibiting the symptoms of COVID-19 and the symptoms cannot be associated with another illness.”

It is important to understand what the CDC actually says about quarantining and re-testing. It is also important to understand that these are guidelines. As new information becomes available, the guidelines will change.

From the CDC guidelines on when to quarantine accessed 15 August 2020: Who needs to quarantine?

CDC: “People who have been in close contact with someone who has COVID-19 — excluding people who have had COVID-19 within the past 3 months.”

CDC: “People who have tested positive for COVID-19 do not need to quarantine or get tested again for up to 3 months as long as they do not develop symptoms again. People who develop symptoms again within 3 months of their first bout of COVID-19 may need to be tested again if there is no other cause identified for their symptoms.”

Indeed, my reaction to the news coverage and the CDC guidelines was it is a complete oxymoron to make statements like: You are “protected” (have immunity) for 3 months UNLESS you get symptoms again. If you were protected, presumably you wouldn’t get symptoms again.

What the guidelines mean: Immunity is likely strong enough in people who have had COVID-19 within the past 3 months that they will not contract COVID-19 again from coming into contact with someone has COVID-19 within that 3 month window. Immunity is likely to last at least 3 months.

What the guidelines mean: If a person who has had a positive COVID-19 test does not need to get re-tested for COVID-19 within 3 months unless they develop symptoms that are not definitely identified as from another cause. For example, they test negative for the flu or for another upper respiratory disease.

What it does not mean: Immunity only lasts 3 months.

What it does not mean: Any person who has had COVID-19 is guaranteed not to contract COVID-19 again.

What it does not mean: A vaccine will only work for 3 months.

What it should not mean: People who have had COVID-19 have 3 months to behave as if they are not at risk anymore.

What it does not mean: People will get COVID-19 over and over again, as implied by “first bout”.

What it does not mean: A person cannot get COVID-19 again or have a recurrence of symptoms within 3 months.

If you have tested positive for COVID-19 and have no symptoms or if you have recovered from COVID-19, the CDC guidance is not a license to party. The CDC guidance is not a license to interact with others without face coverings and to give up on social distancing.

Another piece of information that is critical is to understand what to do if you have tested positive for COVID-19, but you do not have symptoms.

CDC recommends that you quarantine (self isolate) for at least 10 days after having a positive COVID-19 test as long as you do not develop any symptoms.

If you do develop symptoms after testing positive, then you need to

  • wait for 10 days after the symptoms first appear and
  • do not have a fever for 24 hours without taking fever-reducing medicine (aspirin, ibuprofen, acetaminophen, naproxen)
  • other symptoms are improving

Ph.D. scientist with a passion for scientific communication and > 20 years editorial experience

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