Yes, multiple respiratory viruses circulated heavily throughout 2023, and if you or people around you have been dealing with a persistent cough, you’re far from alone. COVID-19, influenza, RSV, and a resurgence of a bacterial infection called “walking pneumonia” all contributed to widespread coughing illness, particularly in the fall and winter months.
What Was Circulating in Late 2023
Three major viruses co-circulated during the 2023-2024 fall and winter season: COVID-19, influenza, and respiratory syncytial virus (RSV). All three cause cough as a primary symptom, and all three peaked during the colder months. The overlap meant that at any given point in late 2023, multiple viruses were responsible for the wave of respiratory illness people were experiencing.
On top of those three, a bacterial infection caused by Mycoplasma pneumoniae surged back after being nearly absent during the pandemic years. The CDC reported that test positivity for this pathogen rose from 0.7% to 3.3% over the course of 2023, peaking in late August. This infection is commonly known as “walking pneumonia” and is a major cause of lingering cough, especially in children and young adults.
Human metapneumovirus (hMPV), a less well-known respiratory virus, also continued circulating. Testing for hMPV increased 92% compared to pre-pandemic levels, though the percentage of positive tests during the 2023-2024 season was 2.6%, slightly below the pre-pandemic median of 3.2%.
COVID-19 Variants in Late 2023
COVID remained a significant source of coughing illness throughout 2023, though the dominant variants shifted multiple times. During the summer and fall, several Omicron descendants traded places as the most common strain. HV.1 peaked at 31.1% of cases by late November 2023, making it the single most prevalent variant at that time. Other strains like EG.5 (peaking at 26.2% in September) and HK.3 circulated alongside it.
By winter 2023, a new variant called JN.1 emerged and spread rapidly. It represented a major genetic shift from previous Omicron strains, with more than 30 differences in the spike protein compared to earlier variants. JN.1 became the dominant strain nationally by early January 2024. For most people, these variants caused familiar symptoms: cough, sore throat, fatigue, and congestion. The constant turnover of variants helped explain why people kept catching COVID even after previous infections or vaccination.
The Flu Season That Kept Going
Influenza A(H1N1) was the dominant flu strain from November 2023 through February 2024, accounting for about 65% of all subtyped influenza A viruses. It was the most common flu virus across every age group, from young children to adults over 65.
What made the 2023-2024 flu season notable was that it stretched longer than usual. As H1N1 activity declined in early spring, H3N2 and influenza B (Victoria lineage) picked up, extending the season well into April. This staggered pattern meant people were getting the flu across a wider window than typical, and some households dealt with multiple rounds as different strains moved through.
Walking Pneumonia Made a Comeback
One of the more distinctive cough illnesses of 2023 was the return of Mycoplasma pneumoniae infections. This bacterium had been circulating at very low levels since the start of the COVID-19 pandemic, likely suppressed by masking and social distancing. In 2023, it re-emerged globally.
Walking pneumonia typically starts gradually with fever, sore throat, and a cough that slowly worsens over days. Unlike viral coughs that often start strong and taper off, the cough from Mycoplasma tends to build. It earns its nickname because most people feel well enough to go about their daily activities, even though they may cough for weeks. In younger children, symptoms can look different, sometimes showing up as diarrhea, wheezing, or vomiting rather than the classic cough pattern. Serious complications like severe pneumonia or worsening asthma are uncommon but possible.
How Long These Coughs Last
One of the most frustrating things about respiratory infections is that the cough outlasts every other symptom. Research published in the Annals of Family Medicine found that the average cough from an acute respiratory infection lasts about 15 to 16 days, regardless of which virus or bacterium caused it. That’s more than two weeks of coughing after you otherwise feel better.
The study also found that the specific pathogen didn’t meaningfully change how long or how severe the cough was. Whether it was rhinovirus, influenza, COVID-19, or a seasonal coronavirus, people coughed for roughly the same duration. So if your cough has been hanging on for two or even three weeks after the worst of your illness passed, that’s within the normal range for any of the viruses circulating in 2023.
What Actually Helps a Viral Cough
The evidence for over-the-counter cough medications is surprisingly weak. Neither guaifenesin (the expectorant in Mucinex) nor dextromethorphan (the cough suppressant in most “DM” products) has strong clinical evidence supporting its effectiveness. Antihistamines and medicated lozenges haven’t shown clear benefit for cough either.
What does help is simpler than what you’d find in the pharmacy aisle. Staying well hydrated, using saline nasal spray or nasal irrigation, and gargling with salt water can all ease symptoms. Plain, non-medicated lozenges can temporarily soothe a sore throat. For children over 12 months old, honey has evidence behind it as a cough soother. These low-tech approaches are at least as effective as the medications marketed for cough relief.
Signs That a Cough Needs Medical Attention
Most coughs from these circulating viruses resolve on their own within two to three weeks. The symptoms that should prompt a call or visit include a fever lasting more than three days, dizziness, or shortness of breath. These can signal that a viral infection has progressed to pneumonia or that you’re dealing with something more serious than a typical respiratory virus. Children, older adults, and people with chronic lung conditions like asthma are at higher risk for complications from any of the viruses that circulated in 2023.