Clinical Course and Symptoms
Emma Raffman
April 27 2021
April 27 2021
Epidemiology commonly describes infection using four specific timeframes: the induction, latency, incubation, and communicable periods. Induction period describes the time between viral invasion and the start of infectious spread within the body. The latency period is the time between initial infection of a patient and the start of their infectiousness to others. Both of these measurements are currently unknown for SARS-CoV-2. In contrast, the majority of media attention is given to COVID-19’s incubation period, the time between initial infection and start of clinical symptoms. Current guidelines from the WHO and Centers for Disease Control and Prevention (CDC) place the majority of patients within a 2-14 day incubation period, thereby providing the rationale for two week quarantine lengths after potential exposure. As this viral pandemic continues to spread, the fourth and final element, the communicable period, is now gaining increased recognition. Representing the amount of time a patient is infectious to others, initial studies on SARS-CoV-2 have found a patient can remain infectious for up to 21 days and generally infects others 2-3 days before their own clinical symptoms arise.
Since COVID-19’s latency period is shorter than its incubation period, this poses a problem as it implies that a large contributor to spread occurs via carriers who are asymptomatic. At the beginning of the pandemic, research found that 48% of COVID-19 infections were transmitted by patients without any symptoms. As a result of its epidemiologic profile, it is no wonder that SARS-CoV-2 represents a challenging infectious disease. When the disease first started spreading in Wuhan, China, COVID-19 had an estimated Reproductive Number (R0) of 2.5, indicating that more than two additional persons became infected for each one existing patient. This positive R0 explains how quickly the virus spread throughout the world.
However, since the administration of FDA approved vaccines which began ramping up in late January 2021, hospitalizations in the United States have been dropping. By the end of February, weekly hospitalization averages have dropped by up to 17% in a single week. On January 5, 2021, there the United States reported 18,000 hospitalizations in a single day whereas on March 6, 2021, there were only a reported 4,100 hospitalizations. While it is clear vaccines have reduced the spread of COVID-19, it is still paramount to practice social distancing and to wear a mask.
Since COVID-19’s latency period is shorter than its incubation period, this poses a problem as it implies that a large contributor to spread occurs via carriers who are asymptomatic. At the beginning of the pandemic, research found that 48% of COVID-19 infections were transmitted by patients without any symptoms. As a result of its epidemiologic profile, it is no wonder that SARS-CoV-2 represents a challenging infectious disease. When the disease first started spreading in Wuhan, China, COVID-19 had an estimated Reproductive Number (R0) of 2.5, indicating that more than two additional persons became infected for each one existing patient. This positive R0 explains how quickly the virus spread throughout the world.
However, since the administration of FDA approved vaccines which began ramping up in late January 2021, hospitalizations in the United States have been dropping. By the end of February, weekly hospitalization averages have dropped by up to 17% in a single week. On January 5, 2021, there the United States reported 18,000 hospitalizations in a single day whereas on March 6, 2021, there were only a reported 4,100 hospitalizations. While it is clear vaccines have reduced the spread of COVID-19, it is still paramount to practice social distancing and to wear a mask.
Epidemiology commonly describes infection using four specific timeframes: the induction, latency, incubation, and communicable periods.
Image Source: Michelle Tran
Symptoms
Given the pandemic’s continually increasing spread, it is incredibly important to understand the clinical symptoms of a COVID-19 infection. Self-isolating immediately upon detectable illness is paramount, especially given the previously discussed incubation and communicable periods. If any of the following symptoms are detected, you should call your healthcare provider for specific steps.
The presence of multiple primary symptoms warrants such immediate self-isolation at home:
Additionally, some extreme conditions should result in immediate hospitalization:
Finally, certain secondary symptoms have now been described. While not serious enough to presume a COVID-19 infection on their own, they may appear in addition to the primary symptoms discussed above:
In order to combat the spread of COVID-19, new resources have emerged. Of note, people concerned about exposure to SARS-CoV-2 can use either the CDC Symptom Checker or Apple COVID-19 App to find appropriate responses to their symptoms.
Given the pandemic’s continually increasing spread, it is incredibly important to understand the clinical symptoms of a COVID-19 infection. Self-isolating immediately upon detectable illness is paramount, especially given the previously discussed incubation and communicable periods. If any of the following symptoms are detected, you should call your healthcare provider for specific steps.
The presence of multiple primary symptoms warrants such immediate self-isolation at home:
- Fever
- Dry cough
- Shortness of breath
- Tiredness
Additionally, some extreme conditions should result in immediate hospitalization:
- Trouble breathing
- Persistent chest pain and pressure
- Bluish face and lips
- Mental confusion
Finally, certain secondary symptoms have now been described. While not serious enough to presume a COVID-19 infection on their own, they may appear in addition to the primary symptoms discussed above:
- Aches and pains
- Nasal congestion
- Runny nose
- Loss of smell and taste
- Sore throat
- Diarrhea
In order to combat the spread of COVID-19, new resources have emerged. Of note, people concerned about exposure to SARS-CoV-2 can use either the CDC Symptom Checker or Apple COVID-19 App to find appropriate responses to their symptoms.
Featured Image Source: Free-Photos
