THE DELTA VARIANT AND BEYOND--EXPERT COVID-19 UPDATE

I just sat in on a Covid-19 update presented by the Newswise science news service featuring three experts:

Perry Halkitis, a public health psychologist and applied statistician at New Jersey's Rutgers University,

Eleanor Wilson, a medical doctor and infections disease specialist at the University of Maryland, and

David Souleles, Director of UC Irvine's Covid-19 response team, recently retired .Orange County Public Health Director

Delta is for Dangerous . . .

Credit: The Spinoff/ISO FORM LLC

The focus of the update was the emergence and trajectory of the delta variant and what that implies for the US.

Here are some of the key points the three experts made:

--The delta variant is a serious threat in the US and worldwide.

--As recently reported, the level of viremia--the viral load in the bloodstream--from a delta-covid infection is 1,000 times higher than from previous versions of the virus. That's probably what is making it so infectious.

--According to Dr. Wilson, the infectiousness, or "R-nought" value, of the original version of Covid-19 was estimated to be between 1 and 3. Statistically that means that one infected person would pass the virus to one to three others. The beta version's R value was between 4 and 6. The delta variant is 8 or 9. The only virus known to be more easily transmitted is measles, with an R value of 13.

--Unfortunately, the current vaccines appear to offer less protection against delta than against earlier versions of the virus. However, even though they may not completely protect against catching the virus, they are still highly effective at preventing serious illness, hospitalization and death. As such, vaccines remain our most important and urgent line of defense. "If we want to get back to normal life, we need our vaccination rates to be much higher," Souleles says. "That's priority number one to get our lives closer to what they were in January of 2020."

--That doesn't just include the US. The billions of people worldwide who are still not vaccinated are not just at risk personally, but represent a huge reservoir of current and future Covid-19 cases and so a huge opportunity for the virus to continue to mutate and spin off even more dangerous variants. "It's a global problem," says Wilson. "We have to vaccinate everyone. If we give the virus fewer opportunities to replicate, we win."

--All three of the experts were very concerned about the portion of the US population that are not yet vaccinated. They emphasize the importance of recognizing that this is not a monolithic group of dedicated vaccine refusers. Instead, these are individuals with many different issues, including very real medical, scheduling or other practical issues, normal anxieties and fears, such as a fear of needles, along with exposure to partial or incorrect information, and, unfortunately, a substantial number of people with politicized resistance to the vaccine and other protective measures. 

--They advocate both continued public education and persistent one-on-one outreach, aimed at recognizing and addressing each person's specific issues. "The media need to help people figure out what's real and what's not real, people who are being bombarded by misinformation," says Halkitis.  

"It takes a lot of conversation, but you have to keep doing it," says Wilson. To which Souleles adds, "Not just one conversation, maybe three, four or five."

--However, when education and patient one-to-one persuasion don't work, stronger steps may need to be taken. "I'd take a "tough-guy-from-New-York" approach," says Halkitis. "If you live in a civil society and you want to navigate spaces like concerts, restaurants, jobs and schools, you need to be vaccinated. Macron did it in France. If you want your children to go to school, they have to be vaccinated."

--All three agree that we need to track the course of the delta variant and any new variants that emerge with great attention, and that they could easily force a re-instatement of controls that have only recently been lifted. "Where we were six weeks ago is not where we are today," says Halkitis. "The next week will be very significant."

To summarize, the delta variant is highly contagious, surging rapidly, and is a potential game-changer. Everyone is eager to get back to something like the old normal, or on to a less restrictive new normal, but ultimately, it's the trajectory of the virus that will determine that. That trajectory is at least partly under our control through vaccination and other public health measures that we're all too familiar with. 

"We've got the tools," Souleles says. "We've just got to apply them on a broad scale."

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REA 7/23/21

GOOD NEW AND BAD NEWS ABOUT COVID-19

Researchers are constantly trying to refine their understanding of the coronavirus pandemic in order to make meaningful recommendations and accurate predictions. To help with this, they have a suite of mathematical models that, for example, can predict the impact that interventions like social distancing, universal mask-wearing, or stay-at-home orders will have on the trajectory of the pandemic.

What are your chances of finding yourself in a situation like this?
Credit: U.S. Air Force/Staff Sgt. Kevin Linuma

However, as anyone who has ever tried to analyze data knows, the best model in the world is useless if it's fed inaccurate data. This is captured by an acronym that dates back at least to 1963, GIGO--garbage in, garbage out.

Probably the most garbage-laden information about the COVID-19 pandemic is the actual number of people in a given region who have been infected by the SARS-CoV-2 virus. This number is necessary in order to calculate how infectious the virus really is, how quickly it can spread through a population, what proportion of the population remains vulnerable, and, crucially, how deadly it is.

Unfortunately, in the absence of widespread testing and contact tracing, typically only severe cases get confirmed and counted. The trick is to get a handle on how many uncounted cases there are for each confirmed one.

That's the key number which is now providing us both good and bad news.

The bad news is that multiple signs point to there being many more people who have been or are currently infected than the official, confirmed case counts tell us. That's bad because it means that you're much more likely to run into someone carrying and potentially shedding the virus than you and public health authorities probably thought.

The good news is that if there are in fact many more COVID-19 cases than we thought, but if the count of  deaths is reasonably accurate, then the virus may be significantly less lethal than we thought in terms of the number people who die compared to the total number who catch the virus.

Here are some relevant data points:

--Out of 3,330 people tested for antibodies to the SARS-CoV-2 virus in Santa Clara County, California, 1.5 percent tested positive. That doesn't sound like much, but it implies that the actual number of cases in that county is 50 to 85 times greater than the confirmed case count.

--A similar study in Los Angeles County found an infection rate between 2.8 and 5.6 percent among adults. Compared to the 8,000 confirmed cases at that time, it implies a true incidence of infections between 27.5 and 55 times greater than the official count.

--New York State has turned out to be the unfortunate epicenter for the virus, with more than 288,000 confirmed cases and more than 22,000 deaths to date. When 3,000 people in 19 counties were tested for antibodies, 13.9 percent tested positive (and a remarkable 21.2 percent in New York City). Those numbers indicate that there have been at least 10 undocumented cases in the state for every confirmed case.

The picture is still blurry--we need much more testing, not only to make the models and their predictions more accurate, but, along with contact tracing and effective isolation, to be able to get our lives and the economy back to normal.

Critics tell us that the above numbers must be scrutinized with care. Statisticians point out that when the incidence of a disease is low, a less-than-perfect test can produce enough false positives to significantly blur the picture.  Others point out that it is hard to match these indicators of a more widespread but milder and much less lethal illness with well-documented clusters of cases and fatalities, as we saw on several cruise ships.

Still, if we squint, it looks as though there are probably ten times or  more actual cases of COVID-19 than confirmed cases.

So again, when you go out, someone comes to your door or you find yourself among a group of people, anyone you're close to is 10 times more likely to be contagious than you might have thought.

But that also implies that the SARS-CoV-2 virus may well be ten times less lethal than we've been told so far; it may kill just two out of a thousand cases rather than the more frequently cited estimates of from 7 to 34 out of a thousand. From the point of view of the population as a whole, that's definitely good news.

However, if you, like 92 million other Americans, are over 65 or have an underlying medical condition such as hypertension, diabetes or obesity,  you remain at high risk of serious illness or a miserable death from the virus. For those at high risk, the crucial, and potentially vital take-away is the fact that there may be 10 times more potential sources of contagion outside your door than you thought.

Please take care!