COVID-19 Disease

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Last reviewed
April 21, 2021

COVID-19 Disease 

Since 2019, the US Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have been closely monitoring the worldwide outbreak of a novel coronavirus known as SARS-CoV-2, which is causing the coronavirus disease 2019 (COVID-19) in humans.

The U.S. CDC reported more than 80% of COVID-19 deaths occurred in people over age 65.

Among 378,048 death certificates listing COVID-19 in 2020, 97% had a co-occurring diagnosis of a plausible chain-of-event condition (e.g., pneumonia or respiratory failure) or a significant contributing condition, hypertension, diabetes, or both. And the CDC confirmed having obesity tripled the risk of hospitalization due to a COVID-19 infection.

Since its emergence in December 2019, no known biological biomarker predicts the risk of a SARS-CoV-2 infection leading to COVID-19 severity, says the CDC.

COVID-19 Preventive Vaccines

The COVID-19 vaccine development landscape includes various innovative platforms, says the U.S. FDA. To review a listing of experimental COVID-19 vaccines, please visit this CoronavirusToday webpage.

COVID-19 Disease Symptoms

The CDC announced on March 3, 2020, that a significant portion of individuals infected with the SARS-CoV-2 coronavirus lack symptoms (“asymptomatic”) and that even those who eventually develop symptoms (“pre-symptomatic”) can transmit the virus to others for several days before showing symptoms. People with COVID-19 disease have reported a wide range of symptoms that may appear 2-14 days after exposure to the SARS-CoV-2 virus.

This means that the virus can spread between people interacting nearby—for example, speaking, coughing, or sneezing—even if they do not exhibit symptoms.

The CDC announced the most common symptoms of COVID-19 disease are fever, tiredness, and dry cough. Some patients may have a loss of smell, with varying combinations of additional symptoms such as confusion, abdominal pain, and shortness of breath, which are not widely known as COVID-19 symptoms, yet are hallmarks of the most severe forms of the disease.

On October 1, 2020, a study suggested that recent loss of smell is a particular COVID-19 symptom and should be considered more generally in guiding case isolation, testing, and treatment of COVID-19. This data indicated greater potential importance of anosmia, as fever was present only in 42.7% of individuals testing positive, versus anosmia being present in 64.6% (34.7% of those not suffering from fever).

A study published by The Lancet on November 3, 2020, confirmed that anosmia is the single most predictive symptom of a positive swab test across different age groups, with odds ratios ranging from 13.67 (95% CI 11·65–16·02) for the older group to 20.86 (18·62–23·4) for the younger group.

People at Risk from COVID-19 Disease

COVID-19 is a new disease, and scientists are still learning how it spreads. Data published by the U.S. CDC indicates people can catch the COVID-19 disease from others who have the SARS-CoV-2 virus. Older people, and those with underlying medical problems such as obesity, high blood pressure, heart problems, or diabetes, are more likely to develop serious illnesses.

On March 8, 2021, and October 6, 2020, the CDC stated, 'Obesity increases the risk for severe COVID-19–associated illness. Obesity was a risk factor for hospitalization and death, particularly among adults aged <65 years. These findings highlight clinical and public health implications of higher BMIs, including the need for intensive management of COVID-19–associated illness, continued vaccine prioritization and masking, and policies to support healthy behaviors.'

Furthermore, children of all ages, including infants, appear susceptible to COVID-19 disease because the SARS-CoV-2 coronavirus is novel, which means infants cannot obtain protective antibodies from their mothers. However, the severe disease appears to be very uncommon. As of September 10, 2020, the AAP data indicated 0.01% of child cases in the USA resulted in death.

At the end of 2020, the CDC reported (888) COVID-19 related hospitalization were by children less than five years of age.

The CDC confirmed as of January 31, 2021, most adults hospitalized for COVID-19 were older, obese, and had comorbidities such as hypertension, cardiovascular, and metabolic diseases. 

Recent NIH-funded studies suggest that one reason some otherwise healthy people become gravely ill may be previously unknown auto-antibodies in their immune systems, which hamper their ability to fight the virus. And these new findings in hundreds of racially diverse people with life-threatening COVID-19 found a small percentage of people who suffer the most severe symptoms carry rare mutations in genes that disrupt their antiviral defenses.

Additional clinical evidence suggests a person's blood type may play a role in COVID-19 susceptibility. A study from Denmark published on October 14, 2020, found blood group O is associated with a decreased risk for contracting SARS-CoV-2 infection. And a second study found COVID-19 patients with blood group A or AB appear to exhibit a greater disease severity than patients with blood group O or B.

And a third study published on November 24, 2020, based on a cohort of 225,556 people in Ontario, Canada, found the O and Rh− blood groups may be associated with a slightly lower risk for SARS-CoV-2 infection and severe COVID-19 illness. Of the study participants infected with the new coronavirus, the lowest unadjusted probability of SARS-CoV-2 infection was among the O− blood group (2.1%). The highest was in the B-positive blood group (4.2%).

 However, other studies found symptomatic individuals with blood types B and AB who were Rh-positive were more likely to test positive for COVID-19, while those with blood type O were less likely to test positive. There is conflicting research about blood types and COVID worldwide, finding links between increased susceptibility in people with type A and/or decreased risk with type O, while other studies found no links.

A study published on March 3, 2021, concluded by saying, 'Whatever the possible contribution of ABO(H) antigens to infection and possible disease progression, the ability of the SARS-CoV-2 to interact with the blood group directly A antigen uniquely expressed on respiratory epithelial cells provides clear evidence of a direct association between SARS-CoV-2 and the ABO(H) genetic locus.'

On March 17, 2021, Hayley Gershengorn, M.D., said in an American Thoracic Society press release, 'after accounting for other differences, individuals of all races and ethnicities living in the highest population density neighborhoods had 2.5-fold higher odds of test positivity than those living in areas with the lowest population density.'

COVID-19 and Pregnant Women

The U.S. CDC says, 'although the overall risk of severe illness is low, pregnant women are at an increased risk for severe illness from COVID-19 when compared to non-pregnant people. Certain underlying medical conditions and other factors, such as age or occupation, can further increase a pregnant person’s risk of developing severe illness.

If a woman is pregnant and part of a group recommended to receive a COVID-19 vaccine, that person should talk to a healthcare provider. This will help make an informed decision about whether to choose to be vaccinated, says the CDC.

COVID-19 Disease Diagnosis

COVID-19 disease is diagnosed by a healthcare provider when a sample is tested via reverse transcription-polymerase chain reaction (RT-PCR) to determine the presence of viral RNA. Various antibody tests detect if you have an immune response due to past exposure to the SARS-CoV-2 virus.

COVID-19 Long Term

Most COVID-19 patients experience mild symptoms and typically recover within a few weeks. However, as the pandemic continues to unfold, the medical world is learning that many organs besides the lungs are affected by COVID-19. Some patients continue to experience symptoms that can last for weeks or even months after recovering. According to the US CDC, multi-year studies have investigated the long-term effects of COVID.

Coronavirus FAQs

Note: Content sourced from the CDC, WHO, various governments, news agencies, social media networks, and the Precision Vax news network. All of the posts have been review by medical professionals, such as Dr. Robert Carlson.