Internal CDC documents support the high transmission rate of the Delta variant and put the risk in easier-to-understand terms. The documents also show that breakthrough infections in the vaccinated make people about as contagious as those who are unvaccinated.
The new report, published in Morbidity and Mortality Weekly Report (MMWR), also reveals the delta variant likely causes more severe COVID-19 illness.
Given these recent findings, the CDC advises that the agency should “acknowledge the war has changed.”
A ‘Pivotal Discovery’
CDC Director said in a statement that the MMWR report demonstrates “that delta infection resulted in similarly high SARS-CoV-2 viral loads in vaccinated and unvaccinated people.”
“High viral loads suggest an increased risk of transmission and raised concern that, unlike with other variants, vaccinated people infected with delta can transmit the virus,” she added. “This finding is concerning and was a pivotal discovery leading to CDC’s updated mask recommendation.”
The report investigators analyzed 469 COVID-19 cases reported in Massachusetts. The infections were associated with an outbreak following multiple events and large gatherings.
Notably, 346 infections or 74% of the cases occurred in fully vaccinated individuals. This group had a median age of 42 and 87% were male. Also, 79% of the breakthrough infections were symptomatic.
Researchers also identified the delta variant in 90% of 133 specimens collected for analysis. Furthermore, viral loads were about the same between samples taken from people who were fully vaccinated and those who were not. Four of the five people hospitalized were fully vaccinated. No deaths were reported.
There will be situations where vaccinated people get infected, because the amount of the virus overwhelms the immune protection.
What is new that is concerning is that people who are vaccinated still have the potential to transmit the virus to the same degree.
Can a person who has completed a COVID-19 series spread the infection?
Because the delta variant is much more contagious than the original strain, unvaccinated persons need to get vaccinated because is nearly impossible to avoid the virus indefinitely, this new data highlights that vaccinated persons, if they become sick, should still seek COVID-19 testing and should still isolate, as they are likely contagious.
More Contagious Than Other Infections?
The Delta variant is about as contagious as chicken pox, for example, the only key thing to note is that this does not mean that COVID-19 delta variant mechanism of spread is the same as chickenpox and Ebola, the primary means of spread of COVID-19, even the Delta variant, is via droplets. This also means each person infected with the Delta variant could infect an average of eight or nine others.
In contrast, the original strain of the coronavirus someone was likely to infect about two other people on average.
The CDC notes that the Delta variant is now more contagious than Ebola, the seasonal flu, or smallpox.
These comparisons are one tangible way of explaining why the CDC recommended a return to masking in schools and other indoor spaces for people – vaccinated and unvaccinated.
In comparing the delta variant to other infections, the Delta variant is so different that the CDC considers it is almost acting like a new virus altogether.
Trust but Verify
Many experts are quick to note that vaccination remains essential – in part because a vaccinated person also walks around with a much lower risk for severe outcomes, hospitalization, and death. The CDC points out that vaccination reduces the risk of infection 3-fold.
Even with this high amount of virus, [the delta variant] did not necessarily make the vaccinated individuals as sick.
It has become essential for everyone to get the COVID-19 vaccine, especially as cases across the country continue to rise. Unequivocally vaccines protect you from the virus.
