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9th January 2023
An analysis by US researchers suggests that only some of the post COVID-19 condition symptoms can be uniquely attributed to infection with the virus when compared to the post-infection symptoms induced by other, common viral infections.
Post COVID-19 condition which is also commonly referred to as long COVID, is defined as the continuation or development of new symptoms 3 months after the initial COVID-19 infection, with these symptoms lasting for at least 2 months with no other explanation. Although there are a number of specific symptoms that have been recognised, the more common ones have included fatigue, cough, chest tightness, breathlessness, palpitations and myalgia. Nevertheless, it is also known that other viral infections can result in lasting symptoms and myalgic encephalomyelitis or post-viral fatigue syndrome is a common disorder, in which patient complain of exhaustion, fatigue, muscle aches and pains, and invariable psychiatric symptoms such as emotional lability, poor memory/concentration, and depression. Thus it is necessary to have a better understanding of the risks associated with the development of specific symptoms to enable a more accurate characterisation of post COVID-19 condition.
In the present study, the US researchers focused on the identification of the persistent symptoms that could be used to define post COVID-19 condition. They made use of information held in the Cerner Real-World Data, which is large US database that receives input from 122 centres across the US. The researchers looked at a wide range of symptoms and which developed 30 days after an acute infection with either COVID-19 and the common cold, influenza and viral pneumonia. These latter three infections were combined to create a viral respiratory infection (VRI) group and de-identified participants were included if they had at least 365 days of data following their acute infection. In addition, a third cohort which included individuals who did not have any recorded infection with COVID-19 or a VRI were included as controls. Comparisons were then made for COVID-19 vs VRI, COVID-19 vs non-infected controls and VRI vs non-infected controls.
Post COVID-19 condition and subsequent significant diagnoses
A total of 17,487 COVID-19 patients were propensity matched with VRI patients and 15,694 individuals were propensity matched with non-infected controls.
When compared to non-infected controls, COVID-19 infection was a significant and positive predictor, for a diagnosis of palpitations (odds ratio, OR = 1.32, 95% CI 1.17 – 1.49), hair loss (OR = 1.32), fatigue (OR = 1.13), chest pain (OR = 1.10), dyspnoea (OR = 1.09), joint pain (OR = 1.08) and obesity (OR = 1.08). Moreover, the odds ratios were also significantly elevated for these conditions when compared to the VRI group.
However, there were notable differences for some recognised post COVID-19 condition symptoms. For example, there was no difference between COVID-19 and the VRI group for anxiety/depression, myalgia, insomnia and anosmia. While there was a significantly elevated risk of cognitive impairment when comparing COVID-19 and the VRI group, there was no difference between COVID-19 and non-infected controls.
The authors concluded n how infection with COVID-19 was not more significantly associated with an increased risk of some recognised post COVID-19 conditions compared to other common viral infections.
Baskett WI et al. COVID-Specific Long-Term Sequelae in Comparison to Common Viral Respiratory Infections: An Analysis of 17,487 Infected Adult Patients. Open Forum Infect 2022
5th January 2023
Receiving a COVID-19 vaccination has been found to reduce the risk of subsequently developing post-COVID-19 condition (or long covid) although the vaccine effectiveness is low according to the findings of a meta-analysis by US researchers.
Vaccine effectiveness is a measure of how well vaccination protects individuals against a condition but differs from the efficacy measured in a trial, because efficacy cannot predict exactly just how effective a vaccine might be in a larger and more variable population. Nevertheless, real-world evidence suggests that some vaccines, such as BNT162b2, have an effectiveness comparable to that reported in phase III clinical trials. Although in practice, many patients make a full recovery after an acute COVID-19 infection, for a minority, there is the continuation or development of other symptoms. The World Health Organisation has described this as ‘Post COVID-19 condition’ and which occurs in individuals with a history of probable or confirmed COVID-19 infection, usually 3 months from the onset of COVID-19 with symptoms that last for at least 2 months and cannot be explained by an alternative diagnosis.
While the effectiveness of vaccination against COVID-19 is widely accepted, what is uncertain, is whether vaccination reduces the risk of post–COVID-19 condition. This was the subject of the current study by the US researchers who reviewed the literature on the effectiveness of COVID-19 vaccines for post–COVID-19 condition and pooled the results of published studies to allow for a more precise estimate of effectiveness. The team looked for studies that: involved vaccinated and unvaccinated individuals and evaluated the long-term effectiveness of the COVID-19 vaccine. Post–COVID-19 conditions were defined as a wide range of health symptoms that were present 3 or more weeks after having COVID-19. Any studies without a comparison between vaccinated and unvaccinated individuals (or other vaccinated control group) were excluded. The team calculated the pooled diagnostic odds ratio (DORs) for post–COVID-19 conditions between vaccinated (i.e., those who received at least 1 dose of a COVID-19 vaccine) and unvaccinated individuals.
Vaccination and effectiveness against post-COVID-19 condition
A total of 10 studies with 1,600,830 individuals evaluated the effect of vaccination on post–COVID-19 conditions and of which 6, were included in the meta-analysis. The pooled prevalence of post–COVID-19 conditions was 39.1% among those who were unvaccinated and 37.6% among those who received at least 1 dose.
The pooled DOR for post–COVID-19 conditions among individuals who received at least 1 dose was 0.708 (95% CI 0.69 – 0.73), giving an estimated vaccine effectiveness of 29.2% (95% CI, 27.5%–30.8%).
However, vaccine effectiveness varied depending on whether an individual received the vaccine before or after being infected with COVID-19. For example, effectiveness was 35.3% (95% CI 32.3% – 38.1%) among those who received the COVID-19 vaccine before having COVID-19 but 27.4% (95% CI 25.4% – 29.3%) among those who received it after being infected.
The authors concluded that COVID-19 vaccination before and after having COVID-19 provided a low but statistically significant decrease in post–COVID-19 conditions for the variants circulating during the study period. They added that a more standardised definition of post–COVID-19 conditions was also needed both for research and clinical purposes.
Marra AR et al. The effectiveness of coronavirus disease 2019 (COVID-19) vaccine in the prevention of post–COVID-19 conditions: A systematic literature review and meta-analysis. Antimicrob Steward Health Epidemiol 2022
24th November 2022
Research by a Spanish team has revealed how symptoms of post-COVID-19 condition (i.e., long covid) persist in both hospitalised and non-hospitalised patients for at least 2 years following their acute infection with the virus.
It has become increasingly recognised that approximately 10% – 20% of people infected with COVID-19 continue to experience a variety of mid- and long-term effects after they recover from their initial illness. The World Health Organisation uses the term ‘post-COVID-19 condition’ and which refers to the constellation of long-term symptoms that some people experience after they have been infected with COVID-19. A wide range of symptoms have been reported affecting various systems in the body, some of which leading to both cognitive and sensory impairment. In fact, a 2021 scoping review identified more than 100 symptoms and whose prevalence varied significantly and were not explained by data collection approaches, study design or other methodological approaches. To date several reviews have examined post-COVID-19 condition symptoms but have only been able to report on the prevalence up to 1 year following an acute infection. In the present study, the Spanish team set out to explore and compare the presence of symptoms in both hospitalised and non-hospitalised patients after a follow-up period of two years.
Hospitalised and non-hospitalised patient data was collected and a random sample from both cohorts who were infected during the first wave of the pandemic and had not been subsequently re-infected were included. Demographic and clinical data were collected from medical records and invited participants agreed to have a scheduled telephone interview 2 years after their infection and which enquired about the presence of a range of symptoms.
Post-COVID-19 condition symptoms after 2 years
A total of 360 hospitalised patients with a mean age of 60.7 years (45% female) and 308 non-hospitalised patients (mean age = 56.7, 59.4% female) were included in the study. The hospitalised and non-hospitalised groups were assessed after a mean of 23.8 and 23.4 months respectively.
Overall, 59.7% of hospitalised and 67.5% of non-hospitalised patients reported having at least 1 post-COVID-19 condition symptom at their follow-up interview. Dyspnoea was more prevalent at the onset of illness among hospitalised compared to non-hospitalised patients (31.1% vs 11.7%, p < 0.001). In contrast, anosmia was more common among non-hospitalised individuals (21.4% vs 10.0%, p = .003).
Th most frequent condition in both cohorts was fatigue (44.7% vs 47.7%, hospitalised vs non-hospitalised), with a similar level of pain symptoms including headaches (35.8% vs 29.9%), memory loss (20% vs 15.9%) and dyspnoea at rest (3.9% both groups).
In multivariate regression analysis, among hospitalised patients, the number of pre-existing co-morbidities was significantly associated with fatigue (odds ratio, OR = 1.93, 95% CI 1.09 – 3.42, p = 0.02) and dyspnoea (OR = 1.91, 95% CI 1.04 – 3.48, p = 0.03). Among non-hospitalised patients, the number of pre-existing co-morbidities (OR = 3.75) and the number of symptoms at infection onset (OR = 3.84) were both associated with the presence of fatigue.
The authors concluded that their cross-sectional study suggested the presence of at least 1 post-COVID-19 symptom in a large proportion of infected patients and which appeared to be irrespective of disease severity.
Fernández-de-las-Peñas C et al. Post-COVID-19 Symptoms 2 Years After SARS-CoV-2 Infection Among Hospitalized vs Nonhospitalized Patients. JAMA New Open 2022