Long Covid Linked to Loss of Smell, Cognitive Impairment, Shortness of Breath at 1 Year

Barak Mizrahi, MSc

Patients with mild COVID-19 are likely to report symptoms of anosmia, cognitive impairment, dyspnea, weakness and palpitations when experiencing long Covid, according to new data from Israel.

In findings from a retrospective, nationwide cohort assessment, a team of investigators from KI Research Institute in Malal observed key consistencies in long Covid symptoms among people who tested positive from March 2020 – October 2021 that would indicate a sequelae for long Covid cases—a burden of the pandemic virus that has been, to an extent, elusively and broadly described and treated by clinicians.

Led by Barak Mizrahi, MSc, a senior researcher with KI Research Institute, investigators sought to determine the clinical manner and outcomes of long Covid at 1 year post-infection among patients with mild COVID-19. The team also sought any associations between common long Covid burdens and patient age, sex, SARS-CoV-2 variant infection, and vaccination status.

Though most mild COVID-19 symptoms have been observed to resolve within 2-4 weeks of first presentation, long-term sequelae has been increasingly evidenced in individual cases. In countries such as the UK, prevalence of long Covid has been reported in approximately 2.4% of the population.

“It may present with various multi-organ symptoms such as dyspnea, fatigue, myalgia, cough, cognitive dysfunction, chest pain, and palpitations, which vary in prevalence and severity, investigators wrote. “The immunological mechanisms and pathophysiology of long covid are still being studied, but some risk factors have already been identified, including older age; pre-existing comorbidities such as obesity, cardiovascular disease, chronic lung disease, kidney disease, hypertension, and diabetes mellitus; initial disease severity; and female sex.”

Mizrahi and colleagues used electronic medical records from an Israeli nationwide healthcare organization to conduct the retrospective cohort analysis; their data included approximately 1.9 million patients who took a PCR test for SARS-CoV-2 infection during the observed period.

The team sought of risk for any of 70 evidenced long Covid outcomes among unvaccinated patients infected with SARS-CoV-2; patients were matched to uninfected control individuals, adjusted for safe and sex, and stratified by SARS-CoV-2 variant. They additionally analyzed for long Covid outcome risk in vaccinated patients with a breakthrough infection compared to unvaccinated, infected patients.

They found that the following COVID-19 infection outcomes were significantly associated with both the early and later phases of the pandemic:

• Anosmia and dygeusia (HR, 4.59; 95% CI, 3.63 – 5.8)
• Cognitive impairment (HR, 1.85; 95% CI, 1.58 – 2.17)
• Dyspnea (HR, 1.79; 95% CI, 1.68 – 1.90)
• Weakness (HR, 1.78; 95% CI, 1.69 – 1.88)
• Palpitations (HR, 1.49; 95% CI, 1.35 – 1.64)

COVID-19 outcomes including hair loss, chest pain, cough, myalgia and respiratory disorders were significantly increased during the early, but not late, phase of the pandemic in patients.

Investigators noted minor differences in long Covid outcomes among male and female patients, as well as a decreased likelihood of outcomes among children than adults during the early phase of the pandemic.

Indeed, vaccinated patients with a breakthrough SARS-CoV-2 infection were at a lowered risk for dyspnea, but similar risk for the other long Covid outcomes as unvaccinated, infected patients. The team observed consistent outcomes based on SARS-CoV-2 variant infection.

“Although the long Covid phenomenon has been feared and discussed since the beginning of the pandemic, we observed that most health outcomes arising after a mild disease course remained for several months and returned to normal within the first year,” they wrote.

The team concluded that their nationwide cohort analysis suggests mild COVID-19 infection is not conducive to serious or chronic long-term morbidity in patients at 1 year post-infection.

“Importantly, the risk for lingering dyspnea was reduced in vaccinated patients with breakthrough infection compared with unvaccinated people, while risks of all other outcomes were comparable,” they wrote.

The study, “Long covid outcomes at one year after mild SARS-CoV-2 infection: nationwide cohort study,” was published online in The BMJ.