The Bay Area is rapidly backpedaling on indoor masking, with most of the region’s counties now recommending that even vaccinated people don face coverings indoors because of concerns about the highly contagious delta coronavirus variant.
Most COVID-19 vaccines are proving very effective at protecting against severe illness and hospitalization from the delta variant, but breakthrough cases do occur — and some experts have said that the potential for lingering health problems known as “long COVID” gives them pause.
Bob Wachter, chair of the Department of Medicine at UCSF, said that while he is fully vaccinated, the possible risk of long COVID has led him to take stricter precautions again.
“I personally do factor the possibility of getting a mild case of COVID that leads to persistent symptoms … into my own personal calculus that guides my behavior,” Wachter said in an email. “I still don’t want to get it, both because of this unknown risk of long COVID, as well as the small but non-zero risk that I could get a mild case and transmit it to a vulnerable person.”
Here’s what we know about the delta variant and the risk of long COVID.
What is long COVID?
According to the CDC, the post-COVID conditions known collectively as post-acute sequelae SARS-CoV-2 infection, or PASC, are ongoing, returning or new health problems that occur more than four weeks after initial infection. These symptoms can occur in anyone who has had COVID-19. Patients report different combinations of a number of symptoms, which include difficulty breathing or shortness of breath, fatigue, brain fog, coughing, headache, and change in smell or taste.
How many people have developed long COVID symptoms?
The number of patients with long COVID is unclear, since most people who develop COVID-19 are not hospitalized and therefore not tracked by the CDC. An article published in Nature last month cited data from the U.K. Office of National Statistics, which tracked more than 20,000 individuals who tested positive since April 2020 and found that 13.7% had symptoms after at least 12 weeks. The agency defines long COVID as symptoms lasting more than four weeks.
I’ve been fully vaccinated. What is my risk of developing long COVID if I get infected?
The short answer is we do not know for certain yet. John Swartzberg, a UC Berkeley infectious disease expert, said no robust studies have been conducted so far to answer this question. Even anecdotal reports have been few.
However, Swartzberg said his conjecture is that long COVID will be unlikely in fully vaccinated people. “The vaccines considerably suppress viral replication in those individuals that have breakthrough infections,” he said in an email. “Our bodies will have less to contend with during the breakthrough infection and this should make long COVID less likely.”
He said more will be known in the next several months as COVID infections increase due to the delta variant.
Wachter also said some experts believe long COVID is unlikely to develop in fully vaccinated people because of limited viral replication, and added that long COVID clinics have not reported seeing many breakthrough cases. However, he said evidence to support this theory is still lacking.
What happens to those who are infected with the delta variant, whether they are vaccinated or not?
Studies so far suggest the delta variant is 50% more transmissible than the alpha variant, which was 50% more infectious than the original strain. But what about the severity of the variant?
“There is no compelling evidence that the delta variant makes people more ill,” Swartzberg said. “If you are fully vaccinated, it’s unlikely you will get ill if you get infected with the delta variant. If you do get ill, it is very likely going to be a mild disease. It is highly unlikely you will get sick enough to be hospitalized or die.”
He said nationally, unvaccinated people account for 97% of COVID hospitalizations, while in Los Angeles County, that number is 99%.
“The people who are getting long COVID are almost always those that are unvaccinated and get infected,” Swartzberg said.
Monica Gandhi, an infectious disease expert with UCSF, said according to data from the CDC, severe illness from breakthrough cases is rare, accounting for only about 0.002% of those cases.
“With adaptive immunity to fight the breakthrough in most vaccinated cases, we are hopeful long COVID will not occur,” she said.
Kellie Hwang is a San Francisco Chronicle staff writer. Email: kellie.hwang@sfchronicle.com Twitter: @KellieHwang