"We're looking at something that is twice as contagious as anything we've seen before," said Baylor College of Medicine's Dr. Peter Hotez.
Dr. Hotez said the variant is already causing cases to increase in parts of the country. However, experts say you are protected against the Delta variant if you're fully vaccinated.
For previous variants, one dose proved effective for the two dose vaccines. However, in the case of the Delta variant, one dose doesn't appear to be enough.
"In England, where they looked at this very carefully, they found that one dose was pretty effective against the Alpha variant, but now that we're dealing with the Delta variant, one dose is clearly not enough," said City of Houston Health Authority's Chief Medical Officer, Dr. David Persse. "You really need to get that second dose to be protected against the Delta variant."
SEE ALSO: 14 people contract COVID-19 Delta variant in Harris County, according to public health dept.
If you've had just one dose and you have waited more than three or four weeks to get your second dose, Dr. Hotez says it's still not too late.
"You'll get a boost," said Hotez. "You definitely want to get a second dose."
Meanwhile, some are questioning the need for a possible third dose.
Pfizer announced that data showed the need for a booster shot, saying after six months, the efficacy lessens.
However, the FDA and CDC said people that are fully vaccinated don't need a booster at this time.
Dr. Hotez has been saying for some time a booster will be needed, but he doesn't think it's urgent for the Delta variant.
SEE ALSO: 99.75% of Houstonians who died of COVID weren't vaccinated, doctors say
"I don't know that we necessarily need to do that for the Delta variant," said Hotez. "I think the vaccination protection for the two immunizations is somewhat robust, so there's not that urgency."
Instead, he thinks the focus should be on getting Pfizer's full FDA approval for the vaccine and he said if you haven't gotten your dose, now is the time to get it.
"Bottom line is, if you're not vaccinated and you've not recently been infected with COVID and recovered, your luck's about to run out," he said.
As far as research goes, Baylor College of Medicine is part of a trial concerning a booster shot of the Moderna vaccine. It's examining the antibody response to the original strain as well as variants.
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