New research from Tulane University reveals that while mild COVID-19 and influenza both cause lingering lung inflammation and scarring, only SARS-CoV-2 leads to persistent brain inflammation and small blood vessel injury. Meanwhile, the CDC is monitoring a new Omicron-related subvariant, BA.3.2, known as the Cicada variant.
Respiratory illness season brings familiar confusion for patients trying to distinguish between colds, flu, and COVID-19. Common symptoms overlap heavily across infections, including cough, fatigue or low energy, fever, and body aches. Additional signs such as sore throat, runny nose, congestion, headache, shortness of breath, nausea, and reduced appetite can appear with various circulating strains. While loss of taste or smell is now less common with recent variants, it remains a possibility.
Tulane Study Differentiates Long-Term Brain and Lung Impacts of COVID-19 Versus Flu
Even mild cases of COVID-19 or influenza can leave physical traces long after initial symptoms fade. Recent findings published in Frontiers in Immunology by researchers at Tulane University have mapped out key differences in how the two viruses affect the body over time, providing biological insight into why some patients struggle with prolonged recovery.
Using a mouse model to examine tissue after infections had cleared, researchers discovered that both viruses leave similar damage in the lungs. Immune cells fail to fully stand down, and collagen buildup increases, which can stiffen lung tissue and cause labored breathing. However, a distinct divergence occurs during recovery. Following influenza, the lungs initiate a repair response, sending specialized cells to rebuild airway linings. That crucial healing process is largely absent after a COVID-19 infection.
In both infections, we observed lasting lung injury,
said Dr. Xuebin Qin, lead author and professor of microbiology and immunology at the Tulane National Biomedical Research Center, as detailed in the Tulane study findings. But long-term effects in the brain were unique to SARS-CoV-2. That distinction is critical to understanding long COVID.
While neither virus was detected in brain tissue weeks later, subjects that contracted COVID-19 showed persistent brain inflammation and tiny areas of bleeding. Gene expression analysis revealed ongoing inflammatory signaling alongside disruptions in serotonin and dopamine regulation pathways, which control mood, cognition, and energy. These neurological alterations were missing in influenza cases, pointing to a direct biological mechanism behind long COVID symptoms like brain fog and fatigue.
Emergence and Monitoring of the BA.3.2 Cicada Variant
As researchers study post-viral impacts, viral evolution continues. The latest lineage drawing attention from federal health authorities is SARS-CoV-2 Variant BA.3.2, commonly called the Cicada
variant. Identified through global and domestic monitoring systems, BA.3.2 shares lineage traits with recent Omicron subvariants like Nimbus and Stratus.
As of early February 2026, the Centers for Disease Control and Prevention reported that BA.3.2 was detected in nasal swabs from four travelers, three airplane wastewater samples, clinical samples from five patients, and 132 wastewater samples from 25 U.S. states. Federal health officials are evaluating the strain for transmissibility, immune evasion, and clinical severity. Although early data indicates it spreads easily and can infect individuals with prior immunity from past infections or vaccines, the variant has not been classified as a high-concern strain and does not appear to cause more severe disease than recent circulating variants.
Treatment Protocols, Safety Measures, and When to Seek Emergency Care
For most individuals testing positive for current variants, recovery happens at home through rest, hydration, over-the-counter fever reducers, and prescribed antivirals like Paxlovid for higher-risk patients. Health organizations continue to advocate for standard preventative measures, including staying up to date on vaccinations, wearing N95 or KN95 masks in crowded indoor spaces, improving room ventilation, and practicing frequent hand hygiene.
Medical guidance advises contacting a doctor if a fever exceeds 103°F—or 100.4°F in children—persists for more than a few days, or if symptoms worsen after initial improvement. Immediate emergency medical attention is necessary for persistent chest pain or pressure, severe breathing trouble, confusion, extreme drowsiness, dehydration signs, or oxygen levels dropping below 95 percent.
