Pandemic Lessons: How likely are you to run into Covid at a party?

Take this question: Are you likely to find Covid-19 at a party?

Yes.

That’s the simple answer, around here anyway.

“It’s pretty likely right now,” said Dr. Thomas Russo, chief of infectious disease at the University at Buffalo’s Jacobs School of Medicine and Biomedical Sciences.

The complexities come in this next question: Is it smart to go – especially in Western New York, which is currently one of the Covid-19 hot spots in the United States?

The answer depends on your own health status, where – and with whom – you spend your days, and who else is going. It becomes even trickier when you consider that many infected individuals may not show symptoms, Russo said, “because they’ve been vaccinated or partially vaccinated or even fully boosted and may be able to still develop asymptomatic infections.”

We distill the intricacies in this installment of Pandemic Lessons:

How prevalent is the virus here?

Red and spreading.

Look at any current map of Covid-19 cases and you’ll see Western New York, along with most of upstate and much of the northeast, colored in crimson. That’s bad, because deepening shades of red on Covid-19 maps indicate viral spread.

Some facts to consider:

• People are getting infected and dying at an alarming rate. As of last week, the region’s most populated county – Erie – is one of 21 counties in the United States to report at least 50 Covid-19-related deaths since Thanksgiving. Erie County reported 779 cases per 100,000 people in that timeframe, ranking it fourth among those 21 counties.

• Western New York stands out in the state, and not in a good way. The region’s seven-day percentage of positive test results was hovering around 10% last week, making it the only part of the state to consistently land in the double digits. That percentage is about four times higher than New York City, the most populated city in the country.

• Hospitalization numbers are worse than one year ago, with more holidays – and gatherings – to come. Western New York hospitals had a seven-day average of 529 Covid-19 patients as of Dec. 11, and approximately one in every five is in critical care. One year ago – when vaccines were not yet available – 514 people were hospitalized, one of every five of those people were being treated in intensive care, too. Last year, those numbers climbed until Dec. 15, dropped briefly for several days, then shot upward again after Christmas and New Year’s gatherings. That indicates the virus is not going away anytime soon.

Is the virus is likely to be present anywhere we go?

Put it this way: If you’re intent on avoiding the virus at all costs, the odds are not in your favor.

Researchers at Georgia Tech have created an interactive Covid-19 risk map that is continually updated based on real-time data. This Covid-19 Event Risk Assessment Planning Tool allows users to choose the size of an event, adjust for a more conservative projection based on availability of testing and then see the odds of an infected person being present within a group.

On Dec. 13, we used the tool to determine how likely it is that at least one person would be infected in a group of 50 people. Here are the results for a moderate projection:

• In Erie County, there’s a 78% likelihood that at least one person will be infected in a room of 50 people. If the group size drops to 20 people, the risk lowers to 46%. In a group of 100, the risk rises to 95%. The odds in Western New York's other counties were even higher, exceeding an 80% risk for a group of 50. But in New York City, by contrast, the risk was only 41%.

• Most of the United States is lower – especially the South. In Florida, for example, many counties have risk percentages for 50-person groups in the teens or single-digits. But in Florida, most of the map was deep red over the summer. Take it as a reminder that surges don’t last; they go up and down.

Those percentages represent the likelihood of one person in a room having Covid-19. In reality, there could be more – or less, right?

Correct. The likelihood of Covid-19 being present in a particular room is based on four factors, Russo said:

• How many people are in the place.

• How widespread the virus is in that community.

• The immune status of the people, ranging from immunologically naïve (people who have never been vaccinated, nor had Covid-19) to people who have been vaccinated and received a booster shot.

• The previous behavior of the people. “What have people who are showing up to the party been up to for the week to two weeks prior to coming?” Russo said. “Have they been involved in risky behavior, or have they been careful?”

How best can we protect ourselves in the room – and how susceptible are you if you’re close to an infected person?

You likely won’t know if you’re close to someone who’s infected, so taking general precautions is important. The biggest proactive move is getting vaccinated – and if you’re six months out from your initial Pfizer or Moderna doses, or two months from a Johnson & Johnson shot, get a booster shot. Those are now available to people 16 and up.

Don't discount masking, either. A recently published study by researchers from Stanford and Yale reinforced that surgical masks, in particular, help reduce Covid spread. But you have to be willing to do it, and be an example of it. 

Dr. Ashley Styczynski, an infectious disease fellow at Stanford and one of the study's co-authors, noted that role modeling "was one of the key factors that influenced mask wearing" in the study, which included nearly 350,000 people.

She wrote in an email to The News: "We think this is because it not only creates social pressure but also because mask wearing is a visible reminder (as opposed to say, vaccination, which is not inherently visible)."

The questions about immunity and the Omicron variant punctuate the importance of still protecting yourself within a room. Places with higher ceilings and more ventilation are considerably safer than a tight, cramped rathskeller-style bar.

“You don’t need to be close to someone to be sharing air with them,” said Linsey Marr, an engineering professor at Virginia Tech who specializes in the airborne transmission of viruses. “Air easily moves between people.”

Envision the virus moving like cigarette smoke particles, Marr advises. “If the room is poorly ventilated, it can build up in that room,” she said. “But if you have good ventilation, you can easily blow that out of there.”

Density matters too, Marr added, “because if it's really crowded, you’re not going to be able to escape other people’s exhaled breath.”

If you’re hosting an event or a party, what’s the safest thing to do?

Require vaccination, and even booster shots, if the people are eligible.

Here’s an example of the strength of full, boosted vaccination: Russo was hosting an eight-person dinner party at his home. Everyone invited was fully vaccinated, at least two weeks out from their booster shot, and nobody had any Covid-19 symptoms.

“One couple said, ‘Should we test beforehand?’ ” recalled Russo, who said, “No, the likelihood of somebody being infectious here is an extraordinarily low number, and even if someone is infectious, since we all have three shots in our arm, the likelihood of us getting infected is also a very low number.”

That scenario adjusts as more variables are entered. If one of the people at that dinner party has a compromised immune system, for example, the other attendees should take at-home Covid-19 tests as an extra layer of caution.

“That is a critical use of those tests that we need to do more of,” Russo said.

But remember those rapid tests are a screening tool – not a full assurance that you are Covid-free. The only thing guaranteed during this pandemic is that Covid-19 is out there – and, unfortunately, it's easier to come across now than it was before.