New Johns Hopkins model projects COVID-19 resurgence in 3 months

More than half of the U.S. population has received at least one dose of the COVID-19 vaccine. But based on a new scenario model by Johns Hopkins, the next three months are crucial if we want to avoid a resurgence by the fall.

As it stands now, 45% of the U.S. population is fully vaccinated, but Johns Hopkins researchers are seeing those numbers as the perfect gap for a coronavirus resurgence to take hold.

"The rest of the population still has some chance for infection and mortality," said Dr. Shaun Truelove, assistant scientist at Johns Hopkins Bloomberg School of Public Health.

The COVID 19 scenario Modeling Hub came out with four scenarios of what could happen in the upcoming months if vaccination rates don't increase.

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"We have a high vaccination scenario and a low vaccination scenario. Where the high vaccination is assuming that about 86% of the eligible population gets vaccinated, low vaccination scenario is down at 75%. Both of those levels are higher than where we are right now. So we still need some progress to get there," said Dr. Truelove.

Luz Pena of KGO-TV, ABC7's sister station in San Francisco, spoke with Dr. Truelove and Dr. Nevan Krogan, director of the Quantitative Biosciences Institute at University of California San Francisco.

Luz Pena: "In your data we are seeing a decline in the summer. Why do you think there could be a resurgence in the fall?"

Dr. Truelove: "This is a virus that has seasonality to it, and with seasonality and changing climate we see that as the fall comes on a higher potential for transmission."

A key factor driving a potential resurgence is the Delta variant. This is the mutation of the virus responsible for the surge in COVID-19 cases in India. In the US this variant is spreading.

Luz Pena: "Do you believe the Delta variant could become the prevalent variant by the fall?"

Dr. Krogan: "I think the less vaccination that occurs now with different pockets in this country, the more likely that will be. The Delta variant be the most prevalent virus."

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At UCSF's Quantitative Biosciences Institute, scientists are studying closely this emerging variant.

"Preliminarily, it looks like it is also modulating our immune response," said Dr. Krogan.

At Johns Hopkins, their modeling is showing an uptick in transmissibility if people don't get vaccinated fast.

"The more pessimistic scenario is that a new variant is about 60% more transmissible than what we are currently experiencing. That is really based a lot on what is being seen in the UK right now with the Delta variant," said Dr. Truelove.