Between UCSF and Zuckerberg San Francisco General Hospital (ZSFG), the two hospitals recorded at least 233 COVID-19 infections amongst staff members. Of those infected, around 80% were fully inoculated against the disease — but just two vaccinated people were hospitalized in total.

The Delta variant's communicability — which is described as being twice as infectious as the original strain, putting it in a similar league now with chickenpox— has caused widespread concern from not only the Center for Disease Control (CDC) and World Health Organization (WHO), but from the San Francisco Department of Public Health (SFDPH) as well. (At this point in the war against COVID-19, it's safe to say that an indoor mask mandate will be introduced in San Francisco sometime this week.) This strain's ability to spread through a population is a particular point of study and worry in communities with high vaccination rates.

And it’s why the recent surge in breakthrough cases among hospital staff at two of SF's foremost medical centers — ZSFG and UCSF — has caused extra concern.

"More staff are getting COVID than we saw before, and it's mostly vaccinated staff. And that's just because of the easing of restrictions," said Dr. Lukejohn Day, chief medical officer at ZSFG, according to a report by ABC 7. "We are seeing it among physicians, nurses, ancillary staff, we sort of are seeing that across the board."

According to information presented by Day, more than 50 staff members tested positive for COVID-19 in July, and somewhere between 75%-80% of them were fully vaccinated. However, none of them were hospitalized.

“We’re concerned right now that we’re on the rise of a surge here in San Francisco and the Bay Area,” Day continued in a statement acquired by the New York Times. “But what we’re seeing is very much what the data from the vaccines showed us: You can still get COVID, potentially."

A similar story played out last month at UCSF when 183 staff members tested positive for COVID-19; 84% were fully vaccinated and just two people were hospitalized with severe illnesses after being inoculated against COVID-19.

"In some ways, it's a little bit surprising and disappointing that we're here talking seriously about COVID after all this time," said Dr. Josh Adler, UCSF's chief clinical officer. However, if there was no vaccine available, UCSF expects they would have four times as many COVID-19 cases right now — and ICU capacities could be nearly at max, a characteristic we saw during past surges prior to the vaccine rollout.

These breakthrough cases are notable, especially considering their community spread and the environment they were contracted within, but those reports from SFGH and UCSF stand as more evidence of how efficacious COVID-19 vaccines are.

Of the more than 164.2 million people who have been fully inoculated, only 125,682 breakthrough cases have been reported in 38 states, according to data collected by NBC News.

That number translates to less than 0.08%, the network noted — though it's understood that this percentage is likely underrepresented. But the data still stands, as does the sentiment it supports: Get vaccinated because it could very well save your life.

Related: San Francisco Could Introduce Indoor Mask Mandate Next Week Amid Rising COVID-19 Cases

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Image: Courtesy of Wikimedia Commons