The nation's top infectious disease expert says the Indian 'Delta' Covid variant has the same viral levels in vaccinated people who have breakthrough infections as in those who are unvaccinated.
Dr Anthony Fauci told MSNBC on Wednesday that means vaccinated people can spread Delta and explains why the Centers for Disease Control and Prevention (CDC) backtracked on mask recommendations for those who got their shots.
Previous research has indicated that people infected with Delta have 1,000 times more copies of the coronavirus in their respiratory tracts compared to those infected with older strains of the virus.
But the CDC has yet to publicly share new research on Delta transmission among the vaccinated that would back up its new mask guidance. Outside experts are calling for the agency to show them the data.
Vaccinated people can spread Delta just like unvaccinated people, Dr Fauci says
¿¿¿¿ Dr. Fauci: "La Variante Delta ha cambiado todo" "Cuando se observa el NIVEL de virus en la nasofaringe de una persona vacunada que contrae infección con #Delta, es EXACTAMENTE EL MISMO que el nivel de virus en una persona no vacunada que se infecta.
— ciclbh (@ciclbh) July 29, 2021
Ese es el PROBLEMA"@MSNBC pic.twitter.com/vdvs4CvgzB
Since the start of the pandemic, one common metric used by scientists is 'viral load' - a measurement of how many copies of the coronavirus are in a patient's body.
When patients have a higher viral load - more copies of the virus - they're more likely to give the virus to someone else.
As the coronavirus has mutated into new variants, its viral load has increased. Delta is now the most contagious variant for this reason.
In fact, according to Fauci, Delta is so contagious that even vaccinated people can spread it.
'We have a Delta variant that has changed the entire landscape,' Dr Fauci said on MSNBC on Wednesday night.
Nationwide, the variant is causing over 80 percent of cases - and in some regions, that number is upwards of 90 percent.
'When you look at the level of virus in the nasopharynx of a vaccinated person who gets a breakthrough infection with Delta, it is exactly the same as the level of virus in an unvaccinated person who's infected,' Fauci said.
'That triggered the change in the CDC guideline,'- referring to the agency's recent backtrack on masking recommendations for vaccinated Americans.
In May, the CDC said anyone who had completed a full vaccination regimen - two shots of Pfizer or Moderna, or one shot of Johnson & Johnson - could go without masks
