ST. PETERSBURG, Fla. — While the U.S. is expanding booster eligibility as more cases of the Omicron COVID-19 variant are identified, we’re getting a sharper insight into its spread.
We asked Dr. Jill Roberts at USF Health about what’s called an R-naught. That's the average number of people a virus typically infects.
The flu has an R-naught of one so for every one person who comes down with the flu, he or she will pass it along to one other person.
The original COVID virus was in the range of 1.5 to three people for each infection. Dr. Roberts says while it will be some time before scientists have enough information to effectively gauge the value for Omicron, it does appear to spread to more people than previous variants.
“Based on the mutations it has, it's probably higher than Delta, so I would guess it's probably higher than 3.2,” Dr. Roberts said. “The majority of our data on Omicron is coming out of a population that is very different than what we have here.”
She says one of the biggest challenges with estimating the transmissibility right now is that in places like Africa, it has been spreading to younger people, and they tend to be asymptomatic.
“When you have it in a location where you’re not doing really robust testing, we won’t know that there were cases,” she added.
Roberts says at some point, it was looking like Delta had an R-naught of 22, but that has since been tweaked to a range of about 3.2 to about eight.
The case detected in Tampa was with someone who had a history of international travel. While there’s been criticism about genomic sequencing for variants in the U.S., it’s easier to find Omicron.
“The way you detect omicron is the test fails, and so you don’t have to do sequencing, you do the normal coronavirus test. It actually uses multiple targets, and when you have Omicron, one of them fails, so it’s called an S-gene failure on the test," Roberts says.
"So the rule is from the CDC, anything that has S-gene failure has to go to sequencing, and so the upside is, there aren’t that many. We do have sequencing capacity here.
"We are able to send those strains out and get them sequenced so pretty much any facility that is doing testing at all for coronavirus should be able to test, detect a suspected Omicron case and then they’re supposed to send them out for sequencing.”
She says the other good news is because the lack of sequencing has been in the spotlight recently, there are some positives.
“Getting it attention means getting it funding, so we’re starting to see funding mechanisms trickle down to increase that genomic sequencing. The capacity is ramping up which means more labs are going to be able to do it.”
She says Delta’s still our main strain right now.
“I think for sure we’re going to start seeing more Omicron. We know that it’s here" she explains. "The limit really of how many we have is how much testing we’re doing and are we able to detect it.
"We know it’s here. We know it will probably move in much like it did in Europe.“
She says the situation there is interesting because they want lockdowns to prevent or slow cases from spreading.
“They’re tired of cases,” Roberts explained.
She says it’s wait-and-see for how Omicron will impact the U.S. but believes it will eventually take off.
Now is the time to get a booster shot, especially as the conversation continues with the approval for ages 16 and older to get a third shot of Pfizer on whether to change the definition of what it means to be fully vaccinated, according to Roberts.
“This conversation has kind of been going on for a little bit of time now. It’s to say that to be fully vaccinated actually means to have three shots—two if it’s J and J, but it really means three shots. And so I would say so,” Dr. Roberts added.
”I know some people are starting to get a little discouraged saying is this booster shot thing going to go on forever and ever and ever. As of right now, three shots that’s it. There’s nothing past three shots. The one exception being if you’re severely immunocompromised.”