National Covid-19 trends, January 23

Here are the latest national Covid-19 trends, according to the CDC and major wastewater surveillance providers:

• New hospital admissions with Covid-19 have decreased 10%, from 5,200 admissions per day during the week ending January 6 to 4,700 admissions per day during the week ending January 13.
• Test positivity has decreased 10%, from 12.8% of Covid-19 tests returning positive results during the week ending January 6 to 11.8% of tests during the week ending January 13.
• Healthcare visits for influenza-like illness have decreased 18% between the week ending January 6 and the week ending January 13.
• SARS-CoV-2 concentration in wastewater has decreased 20% between the week ending January 6 and the week ending January 13, and the national wastewater viral activity level is very high, per the CDC.
• SARS-CoV-2 concentration in wastewater has decreased 11% between January 6 and January 13, per Biobot Analytics.
• SARS-CoV-2 concentration in wastewater has decreased 29% between January 8 and January 15, per WastewaterSCAN.

Two weeks of data now suggest this winter’s Covid-19 surge may have peaked in the U.S., with other respiratory viruses following a similar pattern. Disease levels are still very high across the country, though; it will be several more weeks before the country is out of this surge, and its full impacts will be hidden thanks to dismantled data systems.

The three major wastewater surveillance dashboards (the CDC, Biobot Analytics, and WastewaterSCAN) all report two weeks of declining SARS-CoV-2 levels in the country’s wastewater. WastewaterSCAN, which provides the most up-to-date data, shows the steepest decline, with levels down nearly 30% between January 8 and 15. These three dashboards represent different groups of testing sites and different methods for turning sewage samples into data, so it’s a helpful sign when they display the same trends. Recent data may be subject to change, though, as the dashboards receive reports from more testing sites.

The CDC’s Center for Forecasting and Outbreak Analytics estimates that Covid-19 infections are “growing or likely growing” in only three states and territories, as of January 13: Mississippi, Washington, D.C., and Puerto Rico. Infections are declining, likely declining, stable, or uncertain in the remaining states, according to the center’s analysis, which is based on hospitalizations. Newly hospitalized patients also declined nationally between January 6 and 13, according to the agency.

Omicron variant JN.1 is now causing the vast majority of new infections: the CDC estimates that this variant led to between 80% and 90% of new cases between January 6 and January 20. JN.1 amplified the viral spread driven by holiday travel and gatherings. This is the first time that U.S. Covid-19 cases have been primarily driven by a single variant since early in the Omicron era. Scientists are looking out for descendants from this lineage that may arise from this surge.

In parallel to Covid-19, transmission of flu and RSV is also declining in the U.S. The CDC has marked two weeks of decreasing flu indicators, including lab tests for this virus, outpatient visits for influenza-like illness, and flu hospitalizations. However, many states (particularly in the South and Midwest) are still reporting very high levels of flu-like illness.

While the apparent declines in disease spread are good news, transmission levels of Covid-19 and other common viruses are still high and will remain so for a long time — and the resulting new Long Covid cases may not be identified for months. In fact, there is so much disease going around that many people are getting infected by multiple viruses at once: the CDC’s flu surveillance network, which tracks coinfections at a select group of hospitals, found that 5% of people hospitalized for flu in this network during October and November 2023 also had Covid-19. There may be new implications for long-term illness from such cases.