Surge in mild COVID impacts health workforce

In July, 94 fully vaccinated UC San Diego Health workers had a coronavirus infection with at least one symptom, nearly 19 times the five who got sick in June. The number increased to 176 in August, with an additional 18 testing positive but showing no outward signs of their illnesses.

Though none of those workers got sick enough to check into a hospital, all had to stay home until their symptoms resolved and they tested negative for the virus.

Having so many frontline health care workers calling in with mild cases of the illness is unsustainable, said Dr. Francesca Torriani, a university infectious-disease specialist, as many medical facilities are reporting significant increases in demand for care alongside the summer coronavirus surge.

“We can’t afford to have people missing work and being home 10 to 15 days with a mild infection,” Torriani said. “We need them to be available to work; we can’t afford to lose this vital workforce even temporarily.”

Torriani said a recent request to administer vaccine boosters to frontline workers did not move forward, with state officials deferring to the authority of the U.S. Centers for Disease Control and Prevention. Only Americans with compromised immune systems are currently authorized by the U.S. Food and Drug Administration to receive booster doses.

The Biden administration announced Aug. 18 that boosters of the two-dose vaccines would be available to anyone whose second dose was at least eight months earlier, starting Sept. 20. However, that announcement included language that requires approval from the FDA and the Advisory Committee on Immunization Practices (ACIP), an independent body of medical professionals that makes recommendations to the CDC.

An FDA ruling would then need approval from ACIP.

The current breakthrough case rate in UCSD Health’s workforce received international attention Sept. 1 with the publication of a letter to the editor in the prestigious New England Journal of Medicine.

A team of university researchers — Torriani is the corresponding author — examined administrative data on the vaccination status of its workforce of more than 19,000 people to calculate that overall vaccination effectiveness “exceeded 90 percent from March through June but fell to 65.5 percent in July.”

While the infection rate was still significantly higher in the unvaccinated, the jump was more significant for the fully vaccinated, spiking from 0.3 cases per 1,000 employees in June to 5.7 cases per 1,000 in July. For unvaccinated workers, the rate moved from 4.9 to 16.4 per 1,000.

“The decline in effectiveness is not entirely surprising. Clinical trial data suggested decreased effectiveness would occur several months after full vaccination,” Torriani said. “But our findings indicate that confronted by the Delta variant, vaccine effectiveness for mildly symptomatic disease was considerably lower and waned six to eight months after completing vaccination.”

Dr. Nancy Binkin, a professor of epidemiology in the UCSD School of Medicine and Herbert Wertheim School of Public Health and Human Longevity Science, said the dramatic change in vaccine effectiveness from June to July was likely due to a combination of factors.

“It’s the emergence of the Delta variant and waning immunity over time, compounded by the end of broad masking requirements and the resulting greater exposure risk throughout the community,” Binkin said.

Also, UCSD employees are much more likely than the general population to be tested for infection because they are asked if they are having symptoms when they go to work every day.

However, understanding exactly why the breakthrough case rate is rising at UCSD Health is less immediately important than finding a way to stop the virus from continuing to erode the availability of the medical provider’s workforce.

The powerful advisory committee took a preliminary look at the data surrounding booster doses during a meeting Aug. 30, considering current evidence of waning vaccine effectiveness, with many members expressing skepticism given clear signals in the data that the vaccines are good at preventing severe illness.

“The data to date doesn’t show a remarkable reduction in the effectiveness of the vaccine in terms of preventing hospitalizations and deaths,” said Dr. Beth Bell, a committee member and a public health professor at the University of Washington.

With millions still unvaccinated in the United States, and many more without access to vaccination worldwide, Bell said the evidence suggests that the nation’s public health effort should remain focused on getting more unvaccinated Americans to start their two-dose courses.

“I really think we need to remember that, really, the most important thing that we can do with respect to vaccines is to continue to work as hard as we possibly can to encourage more people to get the primary series,” Bell said.

While ACIP members noted that minor illnesses have “strained health care infrastructure” and that “health care personnel with mild disease cannot work, so prevention of mild disease takes on a greater importance as a public health goal,” there was no rallying cry for immediately offering boosters to frontline workers.

ACIP members acknowledged that many health care providers are going ahead and giving third doses even though they currently are authorized only for the immunocompromised. But officials said vaccinating outside the approved two-dose schedule brings significant risk. As noted in a recent publication from the American Academy of Pediatrics, those who receive off-label doses lose eligibility for compensation from the federal government if they experience a significant side effect. Doctors could lose their immunity from injury claims, their ability to continue providing COVID-19 vaccines and payment for their vaccination services.

Though she said she is aware that some in San Diego County are finding ways to get third doses, Torriani said UCSD plans to follow the rules.

“We can’t go forward without there being a formal OK,” she said.

— City News Service contributed to this report. ◆