Immunity to the SARS-CoV-2 Coronavirus is still a mystery to science. But a study to be conducted in Costa Rica will seek to answer some of the most important questions. The authorities of the Costa Rican Social Security Fund (CCSS), the Ministry of Health, and the Costa Rican Agency for Biomedical Research (ACIB) announced this October 23 the study “Respira”, which will investigate the immunity to SARS-CoV-2 between the Costa Rican population.
This research will seek to know how the immune system behaves against the Coronavirus: how long it takes for antibodies to decay, what factors affect the immune response, and what happens after people recover.
For this, the study will seek to recruit 3,000 volunteers in total: 1,000 who have already been infected with COVID-19 since March and 2,000 who have not yet been infected (known as the control group). In both groups, people will be randomly selected.
The study will have two aims: one of them will show long-term results (2 years), while the other will give preliminary results with people who have already been infected. The latter would give the fastest results. The scientific director of ACIB, Rolando Herrero, assured that they expect preliminary results with 300 volunteers is in a period of six to eight months.
“What we want to do is take cases that have already been cured for six months, that fell ill in March. Others who got sick in April and so on. (…) Thus we can already say that the antibodies of those who were infected before are of such a level, while those that were infected only a month ago are of another level,” he said.
GMA as the main zone
The main recruitment area will be in the Greater Metropolitan Area, since most of the COVID-19 cases are there. However, areas of Guanacaste and Puntarenas will also be included. The scientists will seek to take saliva samples from the participants on a monthly basis and will begin to invite them to collaborate in the study starting next week, through visits and phone calls.
This study is different from the one currently carried out by the CCSS with equine antibodies, since it will not test any treatment in the volunteers. Rather, it will only administer saliva tests to the participants.
Still, the investigation is an important achievement for the country, according to the President of the CCSS, Román Macaya. Scientists will be able to take advantage of the institution’s qualified staff and a well-educated population.
“It will generate information that will be used in Ministries of Health and health entities around the world. It is done in Costa Rica because it is an excellent country to implement this type of study,” said Macaya.
Immunity
The body’s immune response to Coronavirus is one of the big questions about the disease. This is because not enough time has passed to know how the body reacts one year after getting sick.
“We seek to know how the defenses or antibodies act to fight this virus, we want to know how strong they are, if they increase or decrease over time, and most importantly, if they protect people from being infected again,” said Herrrero.
Scientists have documented at least five cases of COVID-19 reinfections in the world. In some cases, the pathology was stronger the second time it was detected. Still, these are to be expected, since it happens with other Coronaviruses.
Science has observed that antibodies to SARS-CoV-2 decay rapidly. A study from the English University King’s College, for example, found that these lowered in a matter of 3 months in most volunteers. However, antibodies are not the only component of the immune system. Other factors – such as T cells, responsible for “remembering” pathogens – could play an important role.
But not enough time has passed yet to know how the immune system behaves after a year of having recovered, for example. This long-term vision will be sought to answer with the study of ACIB and the CCSS.
Contagion
But the research done in Costa Rica will also analyze a second factor: contagion. Scientists will seek to investigate whether there are biological reasons that make people prone to infection.
“This is a model that teaches what is the true biology of the disease, what is the transmissibility of the disease,” said Herrero. “Maybe only 10% of my family members are infected. Despite the fact that these people were very in touch and living together, the transmission did not happen much. In that there are components to study genetic factors”, added the researcher.
Two recent preliminary studies (without peer review), for example, suggested that blood type could be a determining factor. Despite being done in different countries – one in China and the other in Europe – both found that people with type O blood had fewer COVID-19 infections.
But the contagion could also be explained by factors external to people, such as their place of residence, their socio-economic conditions and social activities, for example. The ACIB study will measure both.
“What makes me most contagious? Is it something genetic to be sicker or less sick? To be fatter or skinnier? To be a man or a woman? Or, rather, are they characteristics of the surroundings? Is it a house with only one room? That is what we want to determine,” Herrero said.
