If you look at most charts related to COVID-19 in Arizona — new cases, positivity rates, hospitalizations — you see encouraging downward trends. But there’s one chart that raises concern for Dr. Josh LaBaer with ASU’s Biodesign Institute.
“We are very clearly seeing exponential growth in the U.K. variant in Arizona," LaBaer told reporters Wednesday.
The B.1.1.7 variant, first spotted in the U.K., is known to be more contagious and more deadly, and it is quickly becoming more common in Arizona. The Biodesign Institute has tracked the variant in as many as a third of recent test samples. Earlier this month, the variant had appeared in about 20% of tests. In January, it had appeared less than 1% of the time.
LaBaer said it's a reminder that mitigation measures to limit infections are still critical.
“What drives, without a doubt, the development of variants is just overall numbers of viruses in the community," LaBaer said. "The more people that are infected, the more virus that is around in the community, the more likely there is to be the development of variation.”
LaBaer notes that in other parts of the country, outbreaks are plateauing or beginning to rise again. He said one of the most important steps to preventing another wave of infection in Arizona will be to get more people vaccinated.
But LaBaer said more infectious strains of the virus could ultimately make it more difficult to achieve herd immunity through vaccination. He said the percentage of the population that needs to be vaccinated to reach herd immunity depends on the level of protection vaccines offer and on the level of transmissibility of the virus.
"As we shift from the older strain that's been predominant here to this U.K. variant, which is more transmissible, the numbers we need to achieve herd immunity will go up," LaBaer said.
Even so, LaBaer said he expects Arizona could reach herd immunity by summer with an aggressive vaccination campaign.