Long COVID Outcomes at 1 Year After Mild SARS-CoV-2 Infection

Long COVID following mild infection

Long COVID is a relative term, given that the first COVID-19 case in the United States occurred only 3 years ago. As our experiences with and understanding of SARS-CoV-2 infection have evolved, so too have our approaches to the persisting constellations of symptoms known as long COVID. The passage of time and the huge numbers of accumulated cases across wide swaths of demographic and severity categories are now allowing more refined evaluations of SARS-CoV-2-related syndromes, such as long COVID.

This extensive study compared unvaccinated SARS-CoV-2–infected individuals, vaccinated infected individuals, and uninfected individuals for the presence of 70 separate long COVID outcomes in “early” (30–180 days after infection) and “late” (181–360 days) time intervals. As hospitalized patients were excluded, the included cases were considered “mild” infections. Key findings — expressed as hazard ratios comparing infected with matched control cases — are presented as short- and long-term outcomes.

Short-term outcomes (found only in the first period through 180 days):

• Respiratory disorders — a 2.4-fold difference in the early period
• Hair loss — 1.8
• Chest pain — 1.4
• Myalgia — 1.2
• Cough — 1.1

Outcomes lasting at least 1 year with most declining through time:

• Loss of smell and taste — a 4.6-fold difference in the early period and 3.0-fold in the late period
• Concentration and memory impairment — early: 1.9; and late: 1.7
• Shortness of breath — early: 1.8; and late: 1.3
  • overall burden over one year was 1.1%
• Weakness — early: 1.8; and late 1.3
  • overall burden over one year was 1.4%
• Palpitations — early: 1.5; and late: 1.2
• Streptococcal pharyngitis — early: 1.2; and late: 1.1
  • overall burden over one year was 0.3%
• Dizziness — 1.1; and late: 1.2

Other interesting findings included a minimal difference between males and females, reduced symptoms for children; similar outcomes across wild-type, alpha, and delta variants; and reduced likelihood for shortness of breath in breakthrough (vaccinated) cases.

Overall, we are presented with some reassuring results here. First, the overall burden of long COVID outcomes was relatively low for people with mild (nonhospitalized) infections. Second, most of the long COVID symptoms — if present — declined over time. Finally, vaccination (despite breakthrough infection) reduced prolonged shortness of breath. We will continue to learn more regarding the risks, trajectories, and consequences of long COVID in the months and years to come. For now, keep in mind that vaccination can prevent infection, and even when a breakthrough infection occurs, it is milder. Both of these situations are associated with fewer long-term outcomes.