Enlarge / Parents work on their computers while their son entertains himself at their home in Boston in April 2020. (credit: Getty | Boston Globe )

Respiratory illnesses are raging this fall, slamming children particularly hard. Cases of influenza-like illnesses are off to a startlingly strong and early start this season. RSV—respiratory syncytial (sin-SISH-uhl) virus—continues to skyrocket. A stew of SARS-CoV-2 variants is still simmering in the background. And the rabble of usual cold-season viruses, such as rhinoviruses and enteroviruses, is also making the rounds.

RSV national trends. (credit: CDC )

With the surge in infections, children's hospitals around the country have reported being at capacity or overwhelmed, as Ars has reported before. But another effect of the crush of viruses is a squeeze on the workforce. As The Washington Post first reported Tuesday , the US broke its record last month for people missing work due to childcare problems—such as having children home sick and childcare facilities or schools shuttered due to staffing shortages and sickness.

Outpatient respiratory illness visits. (credit: CDC )

In October, more than 100,000 employed Americans missed work for childcare-related problems, according to data from the US Bureau of Labor Statistics . That is more missing workers than in any other month in recent records, including the entirety of the COVID-19 pandemic, during which many childcare facilities and schools closed down for extended periods. At the height of pandemic-related shutdowns in 2020, the number of Americans missing work for childcare problems only reached the low 90,000s.

Enlarge (credit: CDC )

The US continues to see a dramatic and early surge in respiratory illnesses, which is hitting young children particularly hard and setting records for the decade.

The Southeast region is the most affected by the surge, which is driven by cases of flu, RSV (respiratory syncytial (sin-SISH-uhl) virus), and other seasonal respiratory viruses. Seven southern states—Alabama, Georgia, North Carolina, South Carolina, Mississippi, Tennessee, and Virginia—have reached the highest level of respiratory-illness activity on the scale from the Centers for Disease Control and Prevention. The states are colored a deep purple on the national map, representing the highest of sub-level of "Very High" activity.

Overall, 25 states are experiencing "High" or "Very High" levels of respiratory illness activity, while six have reached the moderate category.

Enlarge / A bottle of influenza vaccine at a CVS pharmacy and MinuteClinic on September 10, 2021, in Miami. (credit: Getty | Joe Raedle )

The pandemic coronavirus' debut wrought universal havoc—not even seasonal flu viruses were spared. Amid travel restrictions, quarantines, closures, physical distancing, masking, enhanced hand washing, and disinfection, the 2020-2021 flu season was all but canceled. That meant not just an unprecedented global decrease in the number of people sick with the flu but also a dramatic collapse in the genetic diversity of circulating flu strains. Many subtypes of the virus all but vanished. But most notably, one entire lineage—one of only four flu groups targeted by seasonal influenza vaccines—went completely dark, seemingly extinct.

Researchers noted the absence last year as the flu was still struggling to recover from its pandemic knockout. But now, the flu has come roaring back and threatens to cause a particularly nasty season in the Northern Hemisphere. Still, the influenza B/Yamagata lineage remains missing, according to a study published this week in the journal Eurosurveillance . It has not been definitively detected since April 2020. And the question of whether it's truly gone extinct lingers.

What B/Yamagata's absence might mean for future flu seasons and flu shots also remains an open question. For a quick refresher: Four main types of seasonal flu have been circulating globally among humans in recent years. Two are influenza type A viruses: subtypes of H1N1 viruses and H3N2 viruses. The other two are influenza type B viruses: offshoots of the Victoria and Yamagata lineages. (For a more detailed explanation of influenza, check out our explainer here .) Current quadrivalent vaccines target season-specific versions of each of these four types of flu viruses.