After 100,000 coronavirus cases, it’s clearer where Californians are getting infected
Longterm care homes, jails and prisons, food processing plants main culprits
UPDATED: May 30, 2020 at 6:32 a.m.
After two-and-a-half months of lockdown restrictions to slow the spread of COVID-19, it’s become clear where Californians are most at risk.
Longterm care homes for the elderly, jails and prisons, food processing plants and social gatherings appear to be the main culprits for repeated outbreaks. And as communities begin lifting restrictions on churches, schools and other large gatherings, the state’s major outbreaks offer clues to where health measures are most needed going forward.
“We’re clearly seeing those clusters of cases occurring in these congregate settings — that is a warning to us that in those types of settings we have to be more vigilant,” said Dr. Lee W. Riley, a professor of infectious diseases and vaccinology at the UC Berkeley school of public health.
A Bay Area News Group review of known major outbreak clusters across California shows they account for a significant share of the state’s more than 100,000 cases:
An outbreak of more than 1,100 infections among inmates and staff at a federal prison complex in Santa Barbara County is among the biggest concentrations of cases in the country.
The nearly 17,000 residents and workers infected in California’s skilled-nursing and residential care facilities for the elderly make up more than 16% of the state’s total COVID-19 cases.
The more than 2,000 who have died at those facilities make up more than half the state’s coronavirus deaths.
And the list of major outbreaks continues to mount: 693 infected at a state prison in Chino, 355 at a Los Angeles jail, 188 at a Visalia nursing home, 180 infected at Central Valley Meat Co. in Hanford, 103 aboard a cruise ship that anchored in Oakland, 71 at a Sacramento church and 106 at a San Francisco homeless shelter.
Smaller case clusters locally in the past week include 39 infected at Morgan Hill seafood wholesaler Lusamerica Fish, 12 at a Cardenas Markets store in Oakland, and four family gatherings in Santa Cruz County, including a Mother’s Day celebration, that together boosted the county’s case total 20 percent.
What makes places like these hot spots? Riley said a lot has to do with the nature of the coronavirus. The infected tend to “shed” the virus for up to five days before they start feeling ill, he said, much longer than the day or two with influenza.
That means people are coming to work and socializing without knowing they are transmitting the virus. Even so, he said it takes about 15 minutes of close contact for the “viral load” to reach a threshold that causes a nearby person to catch the disease.
“You really need close contact for a period of time for this to happen,” Riley said. “The number of viruses it takes to establish and produce an infection is relatively large. Unlike measles, which just needs a few, with this coronavirus, you may need prolonged contact for enough virus to get transmitted.”
Indoor settings also aid transmission of the virus, Riley said. Outdoor breezes quickly scatter airborne virus, thinning their concentration, and sunlight destroys them after about a half-hour. Indoors, concentrated virus can linger in the air much longer and survive on some surfaces for days.
That explains why so many outbreaks occur at institutional settings like jails, prisons and elder care homes, where inmates and residents remain inside together in large numbers and share many facilities. It also explains clusters of cases among crowded, multigenerational households and large family gatherings.
“The virus has the potential to hang around longer than it does outdoors, where the wind’s blowing,” Riley said.
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https://www.mercurynews.com/2020/05/30/after-100000-coronavirus-cases-its-clearer-where-californians-are-getting-infected/