Internal CDC document urges new messaging, warns delta infections likely more severe (WaPo) The delta variant of the coronavirus appears to cause more severe illness than earlier variants and spreads as easily as chickenpox, according to an internal federal health document that argues officials must “acknowledge the war has changed.”
The document strikes an urgent note, revealing the agency knows it must revamp its public messaging to emphasize vaccination as the best defense against a variant so contagious that it acts almost like a different novel virus, leaping from target to target more swiftly than Ebola or the common cold.
It cites a combination of recently obtained, still-unpublished data from outbreak investigations and outside studies showing that vaccinated individuals infected with delta may be able to transmit the virus as easily as those who are unvaccinated. Vaccinated people infected with delta have measurable viral loads similar to those who are unvaccinated and infected with the variant.
New research showed that vaccinated people infected with the Delta variant carry tremendous amounts of the virus in the nose and throat, she said in an email responding to questions from The New York Times.
The finding contradicts what scientists had observed in vaccinated people infected with previous versions of the virus, who mostly seemed incapable of infecting others.
That conclusion dealt Americans a heavy blow: People with so-called breakthrough infections — cases that occur despite full vaccination — of the Delta variant may be just as contagious as unvaccinated people, even if they have no symptoms.
Some of the research may be related in part to an outbreak in Provincetown, Mass., where Fourth of July festivities have led to 882 cases as of Thursday. Nearly three-quarters of those people were fully vaccinated.
It’s still unclear how common breakthrough infections are and how long the virus persists in the body in those cases. Breakthroughs are rare, and unvaccinated people account for the bulk of virus transmission, Dr. Walensky said.
The variant is twice as contagious as the original virus, and one study suggested that the amount of virus in unvaccinated people infected with Delta might be a thousand times higher than seen in people infected with the original version of the virus. The C.D.C. data support that finding, said one expert familiar with the results.
Anecdotes of clusters of breakthrough infections have become increasingly frequent, with groups of vaccinated people reporting sniffles, headache, sore throat, or a loss of taste or smell — symptoms of an infection in the upper respiratory tract.
Executives of the pharmaceutical giant Pfizer predicted Wednesday that vaccine boosters would soon be needed, a declaration that came on the same day the company published data showing that its coronavirus shots remained robustly protective six months after vaccination, providing nearly complete protection against severe disease.
Pfizer’s paper, which has not yet undergone peer review, showed a slight drop in efficacy against any symptomatic cases of covid-19, the illness caused by the novel coronavirus, from 96 percent protection in the first two months after vaccination to 84 percent after four months.
Company officials also presented data showing that a third shot could boost disease-fighting antibodies many times higher than the level achieved by the standard two-dose regimen. They said on a quarterly earnings call that they planned to seek authorization for a booster by mid-August, reiterating the company’s belief that a third dose would be needed to enhance immunity within a year of vaccination.
“There is very good protection in the beginning, and then there’s waning. And when you come closer to six months, [waning] which is even more profound with delta [variant],” Pfizer chief executive Albert Bourla said. “The waning is … more profound for mild cases, but there is a clear waning also for hospitalizations and severe disease.”
Q: Is it still safe to go maskless at big outdoor events, given the increased transmissions from the Delta variant? I know two fully vaccinated people who attended a soccer event in the UK and soon tested positive. Both are in their 30s. Neither was hospitalized, but one was pretty ill.
A: The delta variant is a lot more contagious than previous variants, but it’s still spread the same way as before, and outdoor settings remain much safer than indoor ones. There will be some risk involved going to large outdoor events, especially if people are crowded together, maskless, and speaking or cheering loudly. However, I’d be much more concerned about indoor gatherings associated with these outdoor events; the risk of getting infected at an outdoor baseball game is much lower than the risk of the pre- or post-game indoor party.
f you are in indoor settings with people of unknown vaccination status (i.e. on public transport), you should be wearing at least a 3-ply surgical mask. Consider putting a cloth mask on top to provide a snugger fit–but don’t wear the cloth covering alone. In very high-risk settings, or if you are particularly vulnerable (i.e. you have immunocompromise), you should be wearing an N95 or KN95 mask.
Q: Do you foresee a situation in which outdoor masking (in parks, bike trails etc) will be necessary for vaccinated people?
A: I doubt it. Outdoors, the risk of transmission remains extremely low. Vaccination protects you very well. Masks are another good layer of protection, but I don’t think it will be needed if you already have these two other very good layers of protection.
Related In The Bubble podcasts:
Delta: What to Worry About and What Not to (with Eric Topol) Notes that the Delta variant rise and fall in other countries lasts about 8-10 weeks.
Pfizer CEO Albert Bourla on the Delta Variant, Boosters and Masks Indoors (Part 1) Emphasizes that protection is still good but starts to fall a bit after six months, boosters are recommended and really boost the immune system.