Case Study: Public health data show why COVID spread in Chelsea, and amongst whom

A new study of public health data for 3,302 COVID-19 cases in Chelsea from March 9 to Aug. 3 shows that one of the major reasons for the lightning-quick spread of the disease was the long period of time between when people first noticed symptoms and they finally got tested – as well as more than 30 percent of the positive cases being asymptomatic.

Those two things were found to create a cauldron for the spread of COVID in Chelsea, making it one of the hottest hot-spots on the East Coast in the spring. When combined with other factors in Chelsea, like lots of old folks homes and many essential workers wary to lose their jobs to a COVID test, it was the perfect storm.

Cristina Alonso, a public health doctoral student at Harvard’s T.F. Chan School to Public Health, hit the ground in Chelsea during the height of the surge to help in whatever way possible with the state’s Academic Public Health Volunteer Corps. Though she loaded food boxes at the Collaborative and set up programs for the City, she also began a study of Chelsea’s COVID-19 cases, and released her initial report to the City late last week.

One of the major findings in the report is that people – for all numbers of reasons, likely – waiting sometimes seven days between the first symptoms and getting a test. That was particularly true in the Hispanic community and allowed the spread to move fast.

“The time people were taking between symptoms and being tested was pretty long,” she said. “If there’s one thing that I hope is learned from this report, it’s do not wait to get tested. If you ask the question of what happened in Chelsea, I would say one thing that happened is this time that people took between symptoms and testing. If you can imagine people walking around for a week and how many people were in contact with each other and how many people it put at risk. That’s a big thing that happened.”

Testing during that initial surge certainly wasn’t plentiful or quick, but the analysis showed it took on average about one day to get the test back during the study period, many time less than a day. However, it took most people several days to get tested.

For Hispanic members of the community, the average time between a symptom and a test result was 7.7 days. It was 7.5 days for white residents, 4.9 days for Black/African Americans and 4.3 days for Asian residents.

“One thing that’s important is we don’t use this to place blame on individuals for not getting tested,” she said. “We have to look in Chelsea and remember people here are essential workers and can get replaced on the job. At this time, people in Chelsea were worried about getting a test and being positive and having to go home and then they lose their jobs. They may have been the only person at the time that was bringing home a paycheck. If COVID can cost you your job, it can be stigmatizing and not something someone wanted to know.”

She said one lesson learned is that people need to be tested at all times – as has been recently suggested by state officials – and not just to wait for symptoms. That was because of the second prong of her report, which showed that of the confirmed cases in the time period, 35 percent of people had no symptoms, while 65 percent had one or more symptoms. That meant many people were positive and had no idea.

“One third didn’t have symptoms and people are taking a week to get tested,” she said. “That really speaks to how the epidemic can fly through a community. You have all these people walking around without symptoms and thinking they don’t have it.”

Another interesting find was the people who got the virus.

While essential workers were identified as those who fared the worst in getting the virus, the study found that by and large retired persons were the ones that suffered from COVID-19 more than any others.

Of the cases studied, 35 percent came from retired persons, while 19 percent were from essential workers. 

Indeed, the prevalence to get COVID-19 in Chelsea during the surge was greatest in the retired community and the Hispanic essential worker community, Alonso found.

Interestingly, non-essential workers in Chelsea were not that far behind essential workers in the cases studied. They account for 13 percent of cases, which was only 6 percent behind essential workers.

The retired numbers in Chelsea signify the large numbers of nursing homes and assisted living facilities, and it’s something that she said has to be in context with changes made after the initial surge.

“You’re going to get clusters that show up at assisted living and old folks homes, which is the story of COVID in Massachusetts,” she said. “That’s where the epidemic first hit in Massachusetts and where we got the whiplash…Also because they are vulnerable, they got COVID, they got sick, they went to the hospital and they died. Assisted living and old folks homes are taking it very seriously now. They get tested every day and PPE is plentiful. The data has probably changed now and the numbers would probably look different if I were to look at them for August to December.

A sobering finding in the study is those with co-morbidities – like asthma, cardiac disease, diabetes or hypertension had a much more likely chance to die if they got COVID in Chelsea.

She said the risk of dying if you smoke is about 111 times higher than if you don’t smoke – using that as a measuring stick. For those who have Cardiac Disease, COPD or hypertension, the risk of dying of COVID in Chelsea was higher than a smoker.

Having cardiac disease with COVID made it 132 times more likely that you would die, COPD 131 times and hypertension 116 times.

“Basically, your risk of dying of COVID if you have heart disease conditions is higher than that of a smoker,” she said.

That, she said, is a painful reminder to younger family member who – as is often the case in Chelsea – live in a multi-generational home with grandparents or older relatives.

“Taking a step back, you might be young and in your 20s, but you have to really be thinking about other people in your family if they have these three diseases,” she said. “If your mother, father, grandma or other relative has these three diseases and you give them COVID, it’s not going to go well.”

The final plea by Alonso is that municipalities like Chelsea need to invest in public health data experts like herself, perhaps with the help of state and local funding. When the pandemic hit, the Board of Health was in place, but not up to studying and making key decisions about a global pandemic’s effects on the community. Had there been immediate data analysis in many communities at the Health Department level, things she found in the report could have been found earlier – leading to informed decisions about how to avoid COVID.

“You can’t wait until six months into the pandemic to analyze the data,” she said. “We’ve been waiting for the world to look at us for years in public health, so now is our time to shine.”