Long COVID: Lingering Symptoms in the COVID-19 Pandemic

So far, there have been over 89,000,000 COVID-19 cases and over 1 million COVID-19 deaths in the United States, with cases likely to surge again due to the Omicron BA 2.12.1 variant. Fortunately, the number of hospitalizations and deaths is likely to be only a small part of the Delta and Omicron cases, thanks to the targeted vaccines and antiviral agents. However, we know very little about the complications of COVID-19 infection, which called "Long COVID" (also named Long-Haul COVID) or "Post-COVID-19 Condition". They will continue to affect the lives of those infected for months to years to come.

In this article, we will address 3 questions:

1. What is "Long COVID"?
2. How will the "Long COVID" affect us?
3. Can the vaccine prevent the "Long COVID"?

What is "Long COVID"?

WHO has developed a clinical case definition of Long COVID by Delphi methodology, which includes the following key points:

• Infector: Infection history of SARS-CoV-2;
• At least 3 months since the beginning of obvious symptoms;
• At least 2 months since the beginning of other symptoms not caused by other diagnoses;
• The new symptoms starts from initial infection in both symptomatic and asymptomatically infected individuals;
• The symptoms bring great inconvenience for daily life of patients.

How will the "Long COVID" affect us?

The most common symptoms brought by Long Covid include difficulty breathing or shortness of breath, physical weakness, fatigue, brain (headache, "brain fog" or other cognitive impairment, stroke), nose or nasal cavity (loss of taste or smell), lungs (cough, shortness of breath), heart (pounding heart, heart failure), skin (bruising, rashes), kidney (increased risk of acute kidney injury and kidney failure), diarrhea, insomnia, fever, nausea, vomiting, loss of appetite, dizziness while standing, skin rash, mood changes, menstrual cycle changes, blood in urine and stool.

Source: https://www.gao.gov/assets/gao-22-105666.pdf

However, it may also causes some severe disease, such as pancreatitis, pancreatic injury, coagulation disease, microvessel disease, lymphoid follicular atrophy, reduction of lymphoid T cells and B cells, and myocarditis.

Clinically, it is clear that the infection of COVID-19 does not appear to be directly related to those symptoms. People with mild symptoms can feel sick for months even if the virus is not detected in their bodies.

Of course, these symptoms cannot be simply attributed to Long COVID.

Many symptoms of Long COVID are similar to those of other post-viral diseases, and several trends are being noted as follows: 

• General health: More than half of patients have reported weight loss, fatigue, fever or pain.
• Neurological problems: Nearly a quarter of patients have difficulty concentrating.
• Mental health disorders: Nearly a third of patients have been diagnosed with generalized anxiety disorder.
• Lung abnormalities: Six out of 10 patients had chest imaging abnormalities, and more than a quarter had difficulty breathing.
• Cardiovascular problems: Chest pain and heart palpitations are common.
• Skin conditions: Hair loss or rash occurs in nearly one in five patients.
• Digestive problems: Stomach pain, loss of appetite, diarrhea and vomiting are common illnesses.

Can the vaccine prevent the "Long COVID"?

One of the drawbacks of trying to answer this question is the lack of enough available data. All the detailed data we collected is during the period when the Alpha variant was dominant, but now other variants have emerged.

So up to now, only a small number of data has been collected. With the emergence of Omicron BA2 variant, and the continued emergence of new BA2 subvariants, it is almost certain that the useful data will lag behind what is happening in real time.