While COVID-19 metrics are still down nationwide, there are early signs that the U.S. may be headed for a fall surge.
On Sept. 28, the seven-day average for new cases was 48,806, marking a 22 percent decrease over the past two weeks, according to HHS data compiled by The New York Times. Hospitalizations and deaths are also down.
However, national disease modeling and wastewater surveillance suggest this trend may not last.
Four notes:
1. Nationwide, daily COVID-19 cases are projected to increase 52.4 percent in the next two weeks, according to modeling from Rochester, Minn.-based Mayo Clinic. Forecasts suggest daily average cases will jump from 36,610.3 cases on Sept. 25 to 55,800 by Oct. 9. The nation's case rate is also expected to fall from 16.3 cases per 100,000 people to 17 over the same period.
The number of new COVID-19 hospital admissions and deaths will remain stable or have an uncertain trend over the next four weeks, according to the CDC's ensemble forecasts.
2. Cases are beginning to rise again in the U.K., CNN reported Sept. 27. After falling for nearly two months, data from the National Health Service showed the seven-day average for cases in England and Wales rose 13 percent for the week ending Sept. 17. Hospitalizations were also up 17 percent for the week ending Sept. 19, compared to the week prior. For now, it's unclear whether a new variant is playing a role in the increase.
"Generally, what happens in the U.K. is reflected about a month later in the U.S.," Tim Spector, MD, professor of genetic epidemiology at Kings College London, told CNN. Dr. Spector also runs the Zoe Health Study, which collects COVID-19 data through an app people use to track their symptoms. It has been running since the start of the pandemic and has accurately captured the start of each wave so far.
3. Virus levels in Massachusetts wastewater have increased sharply in recent days, state surveillance data shows. The state tests wastewater from 43 communities daily and first identified an uptick in virus levels Sept. 21. Health officials say wastewater surveillance can serve as an early warning sign, detecting an increase in cases before people undergo testing.
"This uptick is concerning as wastewater sampling is our best leading indicator for transmission," Andrew Lover, PhD, assistant professor of epidemiology at the University of Massachusetts Amherst's School of Public Health and Sciences, told The Boston Globe. "However, we'll need another few sampling days to see if the trend continues before making any firm conclusions."
4. The prevalence of new omicron subvariants is growing. BA.5 remains the nation's dominant strain, accounting for about 83 percent of cases for the week ending Sept. 24, according to the CDC's latest variant proportion estimates. Other omicron relatives have started to gain traction in recent weeks. BA.4.6 is the second most prevalent strain, accounting for nearly 12 percent of cases, followed by BF.7, which accounts for 2.3 percent of cases. The CDC recently began tracking BF.7. Scientists are keeping their eye on the subvaraint since it's been able to gain prevalence in a crowded field of omicron relatives.
Note: Mayo Clinic uses a Bayesian statistical model to forecast cases that automatically updates as new data becomes available. There is an uncertainty interval for forecast values, with lower and upper bounds that are not included in this list. To learn more about the data Mayo Clinic uses to forecast hot spots, click here. Becker's pulled the forecast values Sept. 29 at 8:30 a.m. CDT.