A new COVID-19 variant, XFG, has emerged as the dominant strain in the United States according to wastewater surveillance, even as model-based variant projections continue to show a shifting mix of circulating strains. The contrasting data highlights the ongoing complexity of tracking a moving viral target amid changing reporting patterns and evolving vaccine guidance.
Key numbers from the latest updates
– Nationwide COVID-19 test positivity and outcomes: For the week ending Aug. 16, the CDC reported that 9.9% of 32,998 people tested were positive. That represented a 1.4 percentage-point rise from the prior week. In the same period, the death rate among cases stood at 0.4% (the same as the prior week), and emergency room visits were 1.2% (up 0.2 points).
– Geographic trends in positivity: Western and Southern states—including Washington, Oregon, Idaho, California, Nevada, Arizona, New Mexico, Texas, Oklahoma, Arkansas, and Louisiana—along with Alaska, showed higher percentages of positive tests during the week ending Aug. 16.
– Most common variant by different data sources: Model-based projections for the two weeks ending June 21 showed NB.1.8.1 as the most common variant at around 43%, followed by LP.8.1 at about 31% and XFG at roughly 14%. Wastewater data, released most recently for the week ending Aug. 9, indicated XFG as the newly predominant strain, accounting for about 65% of detected variants nationwide. LP.8.1 accounted for 7%, and LF.7 and XDV.1 each about 5%.
– Shifts in NB.1.8.1 and XFG over time: NB.1.8.1 rose from 0% in early April to 10% in late May, climbed to 24% by early June, and reached about 43% by the end of June. XFG, which was responsible for 0% of U.S. cases through March, reached about 11% by early June and roughly 14% by late June, with wastewater data showing a rapid rise in XFG prevalence later in the summer.
Vaccine guidelines and policy debates
– A policy split is unfolding around who should receive COVID-19 vaccines. The American Academy of Pediatrics released updated guidance on Aug. 19 that diverges from federal recommendations shaped by Health and Human Services Secretary Robert F. Kennedy Jr. Kennedy has suggested that COVID-19 vaccines would no longer be included in the CDC’s recommended immunization schedule for healthy children and pregnant women, a move critics say could narrow access and slow uptake.
– In contrast, state health departments and major professional groups—including the American Medical Association (AMA), the American Academy of Pediatrics (AAP), and the American College of Obstetricians and Gynecologists (ACOG)—have backed continued vaccination for broader groups. The AAP recommends that all children aged six months to 23 months receive the latest vaccine to reduce the risk of serious illness, and that children and adolescents aged 2 to 18 without high-risk factors be offered vaccination if they have not been immunized previously.
– The updated CDC guidance has stopped short of a new, universal recommendation and instead advises parents to consult their child’s pediatrician on a case-by-case basis. This split underscores a broader debate over how to balance public health protection with evolving views on vaccination in different populations.
Symptoms and guidance
– Common symptoms associated with current strains remain broadly similar to prior waves. The CDC lists fever or chills, cough, shortness of breath or difficulty breathing, sore throat, congestion or runny nose, new loss of taste or smell, fatigue, muscle or body aches, headache, and nausea or vomiting.
– Health officials urge seeking medical care for more concerning signs, such as trouble breathing, persistent chest pain or pressure, new confusion, inability to wake or stay awake, or changes in skin color (pale, gray, or blue-tinged) in some individuals.
What this means for readers and communities
– Tracking a moving target: The divergence between wastewater data and clinical sequencing projections highlights the challenges of monitoring a rapidly evolving virus. Wastewater can provide early, broad signals of which variants are circulating, while clinical sequencing offers a more precise picture of which strains are being detected in patients.
– Stay informed and protected: Even as the variant mix shifts, known protective measures remain important. Get tested if symptomatic, consider vaccination according to local guidance and personal risk factors, and follow updated recommendations from trusted health authorities and your healthcare provider.
– Watch for policy changes: With the vaccine guidance landscape evolving, families should stay alert to official updates from local health departments and pediatricians, especially for younger children and pregnant individuals who may face different recommendations than older adults or those with preexisting conditions.
Summary and outlook
The emergence of XFG as the dominant strain in wastewater signals a real-time change in the U.S. COVID-19 landscape, even as other data sources continue to show a complex, patchwork picture of variant prevalence. The ongoing policy debate over vaccination recommendations adds another layer of complexity for families navigating vaccination decisions. Public health officials will likely keep emphasizing layered protection, local data interpretation, and medical guidance tailored to individual risk profiles as the situation evolves. A hopeful note is that surveillance systems are actively tracking these shifts, enabling closer monitoring and a quicker public health response if new concerns arise.