These findings suggest that while the covid phenomenon has long been feared and debated since the start of the pandemic, the majority of mild illnesses do not lead to severe or chronic long-term illness, the researchers say.
Long covid is defined as symptoms that continue or new symptoms appear more than four weeks after the initial infection. In March 2022, an estimated 1.5 million people in the UK (2.4% of the population) reported long-term symptoms of covid, mainly fatigue, shortness of breath, loss of smell, loss of taste and difficulty concentrating.
But the clinical effects of prolonged covid one year after mild infection and their association with age, sex, covid-19 variants and vaccination status are still unclear.
To address this, researchers compared the health of uninfected individuals to those who had recovered from mild covid-19 a year after infection.
They used the electronic records of a large public health organization in Israel where nearly 2 million members were tested for covid-19 between March 1, 2020 and October 1, 2021. More than 70 long covid states were analyzed in a group of infected and corresponding non-infected members. (average age 25 years; 51% women).
They compared the conditions of unvaccinated people with and without covid-19 infection in terms of age, gender and covid-19 variants in the early (30-180 days) and late (180-360 days) periods after infection. During the same periods, the conditions of vaccinated and unvaccinated patients with covid-19 were also compared.
To ensure that only mild disease was assessed, they excluded patients who were hospitalized for more severe disease. Other potentially influencing factors such as alcohol consumption, smoking, socioeconomic status and a number of existing chronic diseases were also taken into account.
Covid-19 infection was associated with a significantly increased risk of several conditions, including loss of smell and taste, impaired concentration and memory, difficulty breathing, weakness, palpitations, streptococcal tonsillitis and dizziness in both early and late stages, while hair loss, chest pain, cough, muscle aches and pains and respiratory ailments improved late.
For example, compared to mild covid-19 infection, non-infected people were associated with a 4.5-fold risk of smell and taste disorders (plus 20 people per 10,000) in the early stages and almost a 3-fold risk (11 per 10,000 people) late.
The overall burden of post-infectious disease during the 12-month study period was highest for frailty (an additional 136 per 10,000) and respiratory distress (107 per 10,000).
When conditions were assessed by age, breathing difficulties were most common, occurring in five of six age groups, but persisted throughout the first year after infection in the 19-40, 41-60, and over-60 age groups.
Weakness appeared in four out of six age groups and remained in the late stage only in the 19-40 and 41-60 age groups.
There were few differences between male and female patients, and children had fewer outcomes than adults in the early stages of covid-19, which mostly improved late. The findings were similar for wild-type, alpha and delta covid-19 variants.
Vaccinated people who became infected had a lower risk of respiratory problems and a similar risk of other diseases compared to unvaccinated infected patients.
The researchers point to some limitations, such as incomplete measurements in medical records, so the data may not fully reflect reported diagnoses and outcomes. They also cannot rule out the possibility that patients with covid-19 use health care services more frequently, leading to higher reporting and increased screening for potential covid-related outcomes in these patients.
Nevertheless, this was a large and detailed analysis of the health records of a diverse population and was one of the longest follow-up studies to date in patients with mild covid-19. And the findings should apply to similar Western populations worldwide.
“Our study suggests that patients with mild covid-19 are at risk for a small number of health effects and most of them improve within a year of diagnosis,” the researchers say.
“Importantly, the risk of long-term dyspnea was reduced in vaccinated patients with breakthrough infection compared with unvaccinated subjects, while the risks for all other outcomes were comparable,” they add.
Source: The Nordic Page