Maybe your neighbors or the man who swam past you at the grocery store. It could be a last-minute supplement to Thanksgiving dinner, or the friend who took off her mask at the gym.
Throughout Los Angeles, COVID-19 is closer than ever.
According to a model released by health officials on Wednesday, one in every 145 people in LA County will be infected with the disease. That’s a big jump from two months ago, when the ratio was estimated at 880 Angelenos 1.
“Our situation is getting worse every day,” Dr. Muntu Davis, a LA county health officer, said at a news conference Wednesday, where the numbers were made public.
The county registered higher-than-ever cases of coronavirus this week, but the latest calculations show that the actual number of patients is even higher. The county uses a mathematical model to determine how many people, whether diagnosed or undiagnosed, are infected with COVID-19 and can spread it to other members of the community based on the number of people hospitalized daily.
Based on data released up to Monday, county data researchers found that about 0.69% of the county’s population, or roughly 69,000 people, are currently able to pass on the coronavirus to others. This does not include people who have had a virus but are no longer contagious, nor those who have become so recently infected that they are not yet contagious.
Across the country, epidemiologists count similar numbers, although the formulas used to make their estimates often differ. Yet the numbers show how health officials are thinking about how widespread COVID-19 is in different parts of the country amid an overwhelming winter ripple.
In Colorado, officials said this week that 1 in 41 people are currently infected with COVID-19. Meanwhile, Chicago officials say it could be as high as 1 in 15.
According to a model created by Jeffrey Shaman, an epidemiologist and team at Columbia University, 3.6 million Americans were infected with COVID-19 as of Sunday. “Most of these infectious individuals are unaware of their infection,” Shaman said in an email to The Times.
Estimates attempt to overcome one of the more insidious features of this coronavirus: 40% of those infected have no symptoms. For those who develop a cough or fever, studies have found that these infections are most contagious to others before these signs appear, which is a matter of serious concern in the next festive period.
“It’s programmed to make us feel safer near our family members or friends, making it more likely to let go of the guard,” said Ali Mokdad, an epidemiologist at the University of Washington. “That’s why winter will be dangerous for us, because we want to convince the public, who has no symptoms, to assume you’re infected and can spread the virus.”
If nearly 1% of the population can be a vector, it becomes more difficult to bend the curve downward. As transmission begins to accelerate, more people in the community have the virus, making the same activities that people have been doing for months becoming more dangerous. These activities make more people sick, further increasing prevalence, and the cycle continues.
“There’s just more COVID milling around our communities,” California Chief Health Officer Dr. Mark Ghaly said Tuesday. “COVID is more likely to become infected just because it’s more accessible and available in our community, even if you behave exactly like you did a month ago.”
In fact, in LA County, health officials said that the people with COVID-19 have not taken more trips to shops, restaurants and workplaces in recent weeks or anywhere else than those who had fallen ill a few months earlier. More people are just getting sick in the same place, they say.
“Even in seemingly benign interactions, there is a risk,” Davis said Wednesday. – The numbers are still alarming.
Davis has also reported a rapid increase in cases and hospitalizations in the county in recent days. The acceleration has prompted the county to stop eating al fresco and introduce a modified stay-at-home regime this week. If the number of cases does not decrease, hospitals will be full in a few weeks and the number of deaths could be in the thousands, officials say.
The county’s prevalence estimate is calculated by the Modeling Group of the Department of Health, which also predicts the need for hospital beds and the county’s transfer rate, known as R. The frequency was added in mid-June to try to help people understand the remote reach of the virus.
To calculate the percentage of those infected, the model assumes that, according to county officials, for every person who is sick enough to be hospitalized with the disease, there are an additional 39 patients but did not go to hospital.
Simply put, the number of people who have recently been hospitalized with COVID must be multiplied by 40. Data researchers adjust this value to exclude people currently in hospital because they do not infect others in the community – and those who may have already had COVID but are no longer contagious. The model assumes that each infected person is contagious for 2-5 days.
Dr. Christina Ghaly, director of the Health Services Department, said that with so many patients who don’t know, Thanksgiving can become a dangerous affair. He cited recent research showing that more than half of the infections come from people who had no symptoms when the virus was transmitted to others.
“They may not know they’re infected … But they’re there and they’re exposing other people to the virus,” he said. “This family meal has become an opportunity for the spread of COVID-19.”
Of the 145 Angelenos, one COVID-infected does not necessarily mean that others are ill. Encountering infectious people can be made safer by masks, social distancing, and limiting time spent together, especially in an indoor environment, experts say.
Nevertheless, the prevalence of COVID-19 in the community is likely to increase only in the coming weeks as the number of cases and hospitalizations continue to increase. The highest estimate ever documented in the county was in late June, when officials said 1 in 140 were infected.
These trends can be reversed with simple behavioral changes, but such an improvement is not guaranteed, Christina Ghaly said.
“We don’t see that happen yet, so I expect the number to continue to rise,” he said.
