COVID-19: Clinical Terms You Should Know

Pamela Cruz. Peninsula 360 Press [P360P].

After almost nine months since the COVID-19 pandemic was declared, the number of infections and deaths is increasing, as well as the doubts regarding clinical terms, since it is often complicated to understand the documents that come out every day regarding the virus.

Below you will find a series of words that will help to better understand the terminology that is so necessary today - and because of the pandemic. 

• Efficiency and Effectiveness

Both terms are often used interchangeably in the context of drugs or, now, in the performance of COVID-19 vaccines, especially in clinical trials, however, there are key differences in both words.

According to the U.S. National Institutes of Health (NIH), efficacy refers to the performance under ideal circumstances, in this case, of a vaccine in clinical trials.

Instead, effectiveness refers more broadly to how well the vaccine meets standards of success in the "real world" after it has been released for consumer use; providing a more realistic picture of a vaccine.

• Quarantine and Isolation

The two words have been used very frequently over the past nine months, especially for actions to be taken when there has been exposure to COVID-19, however, they do not mean the same thing.

Quarantine does not specifically refer to 40 days, but to the separation and restriction of movement for people who were exposed to a disease, in order to see if they become ill. 

The U.S. Department of Health and Human Services (HHS) specifies that in the case of COVID-19, it is for those people who have been in contact with a known case of the virus, but are not yet showing symptoms, so that person will remain at home and away from other people for 14 days after a risk exposure.

Isolation separates people who are sick with a contagious disease from those who are not sick. 

Thus, isolation generally means that the individual has been diagnosed with COVID-19 and is kept away from others by "isolating" himself so as not to infect them, and is usually done within the home, away from other members of the household.

It should be noted that if several people in a household have confirmed COVID-19, it is okay to isolate together, whereas if only one member tests positive, that person should be isolated from the others in the household and all members should be quarantined for 14 days.

• Asymptomatic vs. pre-symptomatic

COVID-19 disease can present with mild to very severe symptoms requiring hospitalization, however there is a big difference between someone who has an asymptomatic case and someone who is pre-symptomatic.

Asymptomatic persons test positive for COVID-19, but "lack symptoms indicative of SARS-CoV-2 infection," but some persons may develop symptoms days after a positive test.

These individuals would be classified as pre-symptomatic at the time of their positive test and will eventually develop symptoms, according to NIH.

• Epidemic vs. Pandemic

The difference between an epidemic and a pandemic is the degree, because according to the Center for Disease Control and Prevention (CDC), an epidemic occurs when there is an increase in cases of disease above normal in a population or limited area (e.g., a single country), while an epidemic can become a pandemic if it spreads to several different countries or continents.

• Outbreak vs. Cluster

The CDC also explains that epidemic and outbreak are two terms that can actually be used interchangeably for the most part, although outbreak is generally used to define a specific smaller geographic area. 

Clustering, on the other hand, often refers to outbreaks on small, specific scales, over a given period of time, within a defined location.

• Community Propagation vs. Transmission

Transmission is technically used to describe how the SARS-CoV-2 virus spreads from person to person, however, community spread is a term used to describe what happens when the disease spreads significantly in a given population without a clear source, the CDC says.

• Mortality Rate vs.

These terms are often confused, but there are important differences between the two. The mortality rate is calculated taking the total population as a reference, while the case fatality rate only takes into account the people affected by a given disease.

Thus, in the case of COVID-19, the case fatality rate (CFR) is the specific number of people with a confirmed diagnosis of COVID-19 who die as a result of the disease. An example of this is: for every 1,000 people diagnosed with COVID-19, one person dies.

Mortality rate, on the other hand, is a more general approximation of the number of deaths occurring within a larger or given population, such as that of an entire country, said the World Health Organization (WHO).

In this sense, an example would be: Out of a population of 100,000 people, two die from COVID-19.

• Hospitalization and ICU (intensive care unit) rates. Vs. Capacity

Hospitalization and intensive care unit (ICU) rates refer to the number of people in a specific area who are hospitalized after a COVID-19 diagnosis, and is compared to the total population of a given area, such as a county, state or country. 

Hospital and ICU capacity, on the other hand, are statistics that describe the burden per COVID-19. The figures are generally expressed as a percentage: the number of occupied beds divided by the number of total beds.

In that case, it is necessary to point out that hospital capacity is not only a question of beds, but of the personnel available to care for patients, the CDC stresses.

• Ventilator and Respirator

Although in Spanish-speaking countries both words refer to the same thing, according to the NIH and the CDC these two devices are not the same. A ventilator, also known as a mechanical ventilator, is a machine generally used in a hospital that blows air through tubes into the patient's airway.

While a respirator, a piece of personal protective equipment, worn over the mouth, nose or face to prevent inhalation of airborne particles, gases or vapors, is a different item than a facemask.

In this regard, the CDC points out that N95 respirators are recommended for health care personnel in clinical settings, but not for the average person due to the severe shortage of such equipment.

• Positivity Rate vs. Prevalence

According to the Johns Hopkins Bloomberg School of Public Health, the positivity rate, also known as the "percent positive rate" or "percent positive," is that of all coronavirus tests performed that are actually positive. 

This is an indicator of whether sufficient testing is being performed and whether enough asymptomatic and mild cases are being evaluated, the university notes.

Prevalence, on the other hand, he said, is a specific number of people who have-or had? COVID-19 during a specific time period, reflecting the number of true-positive individuals in the entire population, not just those who are tested. 

In this regard, he noted that prevalence can help researchers and decision-makers understand the broader picture of the spread of such a virus in a specific area or population.