CDC internal memo calls delta variant as contagious as chickenpox: report

An internal memo from the Centers for Disease Control and Prevention (CDC) reportedly says that the highly transmissible delta variant may cause worse illnesses than other versions of COVID-19 and is more contagious than other leading viruses. 

The document, first reported by The Washington Post, reportedly urges health officials to “acknowledge the war has changed” and cites still-unpublished data showing that individuals vaccinated against COVID-19 may transmit the delta variant just as easily as unvaccinated groups. 

CDC Director Rochelle WalenskyRochelle WalenskyPfizer results offer hope amid worsening pandemic for children FDA panel endorses COVID-19 booster shots for older Americans, rejects widespread use Watch live: White House COVID-19 response team holds briefing MORE cited the unreleased data to justify this week’s change in guidance urging all people, regardless of vaccination status, to wear masks in "public, indoor settings" in areas of the country with "substantial" or "high" levels of transmission of COVID-19. 


According to the Post, the internal memo is a slide presentation shared within the CDC and obtained by the news outlet and in part mentions “communication challenges” regarding viruses in vaccine people, including concerns from local health department about whether vaccines are effective against the delta variant and a “public convinced vaccines no longer work/booster doses needed."

The New York Times, which also obtained a copy of the document, shows that the delta variant could be more infectious than the viruses that cause MERS, SARS, Ebola, the common cold, the seasonal flu and smallpox and is just as contagious as chickenpox. 

A federal official who has seen the CDC research described in the document told the Times that the agency is “very concerned with the data coming in that Delta is a very serious threat that requires action now.” 

Both the Post and the Times reported that the data is expected to be published in full later Friday. 

The Hill has reached out to the CDC for additional information.

Walensky said Tuesday that the new research on the transmission of the delta variant among vaccinated people “is worrisome and unfortunately warrants an update to our recommendations.” 

The updated CDC guidance on masks has fueled businesses and local governments to implement vaccination requirements for workers, and President BidenJoe BidenUN meeting with US, France canceled over scheduling issue Schumer moves to break GOP blockade on Biden's State picks GOP Rep. Cawthorn likens vaccine mandates to 'modern-day segregation' MORE on Thursday directed all federal employees and onsite contractors to show that they are vaccinated or otherwise submit to regular coronavirus testing.