Published Tuesday, May 12, 2020 

By the A.M. Costa Rica staff

It is possible that a person became ill with covid-19 and managed to recover without knowing it since they never experienced symptoms, according to scientists at the University of Costa Rica.

According to specialists and international scientific research published in Germany and the United States, this possibility and research is not just in Costa Rica.

To verify it in the country, solid studies are needed that allow the eventual creation of a complementary test to the diagnosis, capable of being carried out in the country and being inexpensive, the University said in its statement.

This is precisely a task that is already being carried out by a group of scientists from the Faculty of Microbiology and the Institute of Pharmaceutical Research at the University of Costa Rica.

Why is it important to know if there are people who had the disease and recovered without realizing it? With this information, it would allow possible immune individuals to be discovered and the Ministry of Health to have useful data to assess the relevance of the restriction measures.

"It will be very valuable information for the Ministry of Health," said German Madrigal, director of the institute. "For example, knowing how many people experienced the disease, inadvertently and generated antibodies could help to relax restriction measures because the danger of contracting the disease again decreases.”

According to scientists, people already recovered from a viral disease have a low risk of reinfection. It is not yet known if the same thing happens with SARS-CoV-2. Therefore, by finding asymptomatic individuals recovered from covid-19, the long-term behavior of the virus can also be analyzed.

"It is necessary to register asymptomatic people and those who passed the virus without knowing it because we still know very little about SARS-CoV-2," said Ismael Segura Ulate, a molecular biologist. "Identifying people who have already recovered helps to control some populations, such as medical personnel.”

The scientific team at the university has the capacity to generate a complementary test that, unlike the current exam, will take place in Costa Rica and will carry out the test with blood samples.

Using this technique, it is calculated that in three hours or less, patients recovered from covid-19 could be identified, even those who were infected without knowing it.

According to specialists, in order to diagnose a patient with covid-19, a test known as Polymerase Chain Reaction, PCR, is used. Internationally, this method is one of the most important because it allows us to obtain millions of copies of a fragment of the virus and, in this case to know if it is SARS-CoV-2.

However, that method has some limitations. One of them is that it detects the active virus in a specific time frame. In simpler words, there is an expiration date. Therefore, PCR cannot be used when a person has already been in contact with the virus and recovered, because their immune system has most likely already killed the organism.

"PCR is a method of detecting genetic information when the virus is active in the person," Madrigal said. "This test generally only applies to suspicious patients with an obvious picture of symptoms. The latter means that people without symptoms may not be being registered.”

The researchers' goal is to have the scientific knowledge necessary to create the complementary test in the future, which is not intended to replace PCR, but act as an ally in diagnosis, the university said in its statement.

More information on the progress of creating a test to detect patients recovered from covid-19 without symptoms can be reached at the UCR website.


The ministry reported on Monday afternoon, 277 active patients in Costa Rica infected with the covid-19. Active patients are people who currently have the virus.

Authorities provided the following statistics related to the development of the covid-19 in the country:

• Of the 801 infected since the first case was detected in March, 517 coronavirus patients have fully recovered.

• There was an overnight increase of 9 new patients infected with the covid-19.

• The ages of those affected range from 1 to 87 with an average age of 37.

• 21 patients are being treated in public hospitals, where 15 are in recovery rooms and 6 have been reported in an Intensive Care Unit with delicate health conditions. Most of the infected patients are quarantined in their homes.

• 113 foreigners infected, of these 14 entered the country unauthorized and are jailed in the facilities of the  Professional Migration Police in Heredia Province.

• 11,259 people have been ruled out.

• 17,299 medical covid-19 tests have been made.

• Seven deaths have been reported from patients infected with covid-19.

On Sunday night the ministry reported the seventh death of a covid-19 in the country. According to a summary, an 80-year-old foreigner who lived in Alajuela was diagnosed with the virus on May 9. The same day he was admitted into the Intensive Care Unit at Enrique Baltodano Briceño Hospital in Liberia, Guanacaste Province. The patient's nationality information was not provided.

The man had pre-existing high-risk conditions such as his age, high blood pressure disease and chronic obstructive pulmonary disease which made him more vulnerable to covid-19.

On April 20, the sixth death was a 54-year-old Cuban national and Costa Rican resident of Alajuela Province. He was diagnosed with the coronavirus on March 6. That same day he was admitted into intensive care at México Hospital in San José Province. The man had pre-existing conditions such as hypertension, diabetes, smoking, among others which made him more vulnerable to covid-19.

He was one of the first patients confirmed with the virus. Officials identified him as a doctor at the hospital where he was being treated for a lung infection and diabetes. According to the authorities, the man arrived from Panama on Feb. 22 without symptoms at Juan Santamaría International Airport. Days later he went to a hospital where authorities confirmed his infection with coronavirus covid-19.

He was identified as a superspreader of the covid-19. A superspreader is an individual who is more likely to infect others, compared to a typical infected person. According to the authorities, he was linked to 81 people infected with covid-19.

On April 19, a 69-year-old Costa Rican who was diagnosed with the coronavirus on March 25 died. He was admitted into intensive care at the San Juan de Dios Hospital in San José on March 28. He had high blood pressure which increased his risk factor for covid-19 coronavirus, the ministry said.

On April 15, an 84-year-old Costa Rican man who had tested positive for covid-19 on April 1 was reported dead. He was admitted into intensive care at the same hospital, San Juan de Dios, on April 5. The patient suffered from high blood pressure. His pre-existing condition plus his age played major risk factors for contracting coronavirus, said the ministry.

On April 8, the death of a 45-year-old Costa Rican was reported. He entered the country from the U.S. in March, where it is presumed he was infected. He was hospitalized for 10 days in the intensive care of the same hospital, San Juan de Dios.

On March 20 the death of an 87-years-old patient was reported. He was hospitalized in the Intensive Care Unit at San Rafael Hospital in Alajuela Province.

A few days earlier, on March 18 the first patient died, 87. He was hospitalized in the Intensive Care Unit at the same Alajuela Hospital.

The National Distance Education University, UNED, provides a daily updated number of total patients, active and recovered, in each district throughout the country on its Covid-19 Map.

As of Monday night, the pandemic has killed 288,076 patients worldwide according to recent statistics reported by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University.


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Could the antibodies from patients recovered without symptoms be more effective in treating the virus?  We would like to know your thoughts on this story. Send your comments to news@amcostarica.com