Nine in 10 American children have been infected at least once by COVID-19 since the pandemic began nearly three years ago, according to an updated estimate from the Centers for Disease Control and Prevention.

The CDC tracks “seroprevalence” — the proportion of a population with antibodies from a previous virus infection. In data posted Thursday, the agency estimated that 90.3% of children 6 months to 17 years old had evidence of SARS-CoV-2, the virus that causes COVID-19, in their blood. That amounts to nearly 65 million children.

The data only includes antibodies from a past infection, not from vaccination. The information does not indicate whether someone had multiple cases of COVID or how well they might be protected against future infection.

Hawaii was the only state that had a seroprevalence of less than 80% — 77.8%. Idaho and Utah tied for the highest rate at 96.9%. There was insufficient data for North Dakota, South Dakota and Wyoming, while all other states had rates of at least 80%.

The statistics come as the U.S. is battling a “tridemic” of COVID-19 and increased cases of flu and respiratory syncytial virus, or RSV, which poses the greatest threat to young children and older adults.

Meanwhile, vaccination rates among children are lagging, with fewer than 15% having received an updated booster shot.

The CDC recommends people 6 months and older receive updated COVID-19 and flu shots, especially with indoor holiday gatherings increasing in the coming weeks. There is no vaccine for RSV.

The CDC plans to release updated seroprevalence numbers on adults by the end of the month. According to the most recent data available, 48.8% of U.S. adults had been infected with COVID through March 2022.