San Diego Union-Tribune (Sunday)
SURGE IN OUTBREAKS INDICATES DECREASED VIGILANCE
Number a signal of less adherence to masks, social-distancing rules
San Diego County announced 47 community coronavirus outbreaks from Oct. 7 through Oct. 13, the largest weekly total to appear in local public health reports since the pandemic began in March.
Defined as three or more cases from different households who visited the same location in the same 14-day window, outbreaks serve as a barometer of the public’s overall adherence to the mask wearing and social-distancing rules that have so far controlled the virus’ spread.
“The number of cases and the number of outbreaks are certainly tracking upward, and that is concerning,” said Dr. Eric Mcdonald, medical director of the county’s epidemiology department.
And it’s not just San Diego. Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said the frequency of outbreaks is increasing across the nation.
“You now have an outbreak of outbreaks; that’s exactly what it
is,” Osterholm said. “Until people back off of the highrisk behavior that they have, that’s going to continue.”
Besides the obvious health risks associated with becoming infected, an overall increase in the number of outbreaks presents a risk of backsliding in the state’s reopening system, which could, in the span of just a few weeks, force some of the region’s businesses and faith-based organizations to once again operate outdoors only.
Outbreaks, Mcdonald noted, are a core epidemiological tool designed to help public health departments know where to focus resources.
Contacts are made with each location’s ownership to check infection-control procedures and site visits are made for all food-serving locations to observe conditions in person.
While the overall shape of the outbreak curve may signify shifts in adherence to infection-control practices outside individual households, these epidemiological events are not responsible for the bulk of cases detected in San Diego County so far.
To date, only about 3,000 of the more than 51,000 positive cases confirmed through testing have been associated with an outbreak, according to county reports.
It is unclear why the majority of cases are not associated with outbreaks. In some cases, Mcdonald said, people may not be honest about, or even remember, everywhere they have been before getting sick. And the fact that the outbreak definition requires three or more cases from different households means that serial transmission directly from one household to another will not meet the definition.
But that three-household definition does seem to help spot situations where coronavirus has gained the kind of foothold that is likely to generate large numbers of cases very quickly.
For a good example, look no further than San Diego State University, which saw its total number of cases explode, growing from dozens to hundreds shortly after campus reopened on Aug. 24.
Interviews with students who tested positive and those they were closest to before they started showing symptoms quickly revealed several gatherings that met the outbreak definition.
Though most of the gatherings looked too small to generate the kind of rapid growth that positive test results showed, a deeper look, Mcdonald said, showed that spread among the student body seems likely to have been a function of social connections.
“There was no one big huge party with hundreds and hundreds of people,” Mcdonald said. “It was just that there were so many smaller, but yet significant, groups that were occurring all in a short period of time with overlapping social networks.”
A deeper analysis of who was involved in each outbreak yielded a multidimensional Venn diagram of overlapping social circles, revealing a kind of composite party large enough for the virus to spread at rates that would likely have burned out had the gatherings been unconnected.
“If you have multiple events like that of 30 or 40, all of whom have overlapping individuals who attend each, then it’s essentially, in aggregate, it’s a superspreader event, and that’s essentially the dynamic that occurred with San Diego State University,” Mcdonald said.
That pattern, Osterholm noted, is not unique to SDSU. It is a fundamental way that this particular virus spreads pretty much everywhere people come together.
“There are meta superspreader events occurring right now with weddings, funerals, class reunions, birthday parties, community activities, sporting events,” Osterholm said.
While initial public attention was focused on the average amount of time it takes one person to infect up to three others, many have noted in recent weeks that the novel coronavirus seems to have a low rate of dispersal. This means that cases tend to “cluster” in space and time, suggesting that gatherings are more ripe for generating big numbers of infections than other viruses, such as influenza.
Whether this means that the virus simply moves through the air on a human breath more easily, or whether certain individuals simply shed more virus without showing symptoms, is not fully understood.
Having kept up with the literature, Osterholm said his best bet would be a little of both.
“It seems like the environment and the individual, together, are what make the difference,” Osterholm said. “If you have a hot, hot individual in the middle of nowhere, you get nothing. But you put that individual at a wedding eating and drinking and dancing for six, eight hours, and now you’ve got that potential to infect a lot of people very quickly.”
Outbreaks in San Diego County, Mcdonald said, have tended to involve people letting their guard down.
Places of employment, whether restaurants or grocery stores, tend to get high levels of caution from their workforces. But that discipline tends to erode after hours.
Co-workers who spend all day working behind masks may take them off for too long when they go out to dinner off the clock.
This phenomenon, he said, tends to be particularly high among health care workers who are among those who have to be the most meticulous with their on-the-job protections.
“Health care workers, more than anybody else, when they’re outside their work environment, need to feel like they’ve gotten away and are able to relax and do something different,” Mcdonald said. “It’s when people let their guard down outside of areas where they think they should be guarded. That’s a very hard thing to address.”
Where, exactly, these situations are occurring remains a mystery.
Though it does release daily updates on the overall number of outbreaks by type, and it is clear that the largest numbers are occurring in restaurants and businesses, San Diego County has redacted names from outbreak lists obtained through public records requests.
The county has so far made the case that the public’s fundamental right to know specific locations is trumped by its own needs to effectively investigate cases.
In writing and in public statements, county officials have said that releasing names could be used in conjunction with other information to reveal the health status of individuals.
Naming might also, the county argues, make those involved in outbreaks less likely to be forthcoming with case investigators about the locations they visited before getting sick.
In public news conferences, officials have also said that releasing names and addresses could cause a public backlash against locations that have adhered to health precautions but had patrons who did not.
Recently, The San Diego Union-tribune joined a lawsuit first filed by news site Voice of San Diego and local National Public Radio affiliate KPBS that asks the court to determine whether redacting names from the outbreak list is legal.
Felix Tinkov, the San Diego attorney representing the three news outlets, said Friday that a hearing on the matter is scheduled for Oct. 23. The attorney said he will argue that the county has not provided enough evidence that its concerns about releasing names are legitimate reasons to justify redaction.