Quick tests take their first test

As soon as the compulsory quarantine in Vitacura was lifted, Javiera (43) left her house to visit a friend and go find a bed that had been given to her. She came out quiet after spending weeks locked up, since, she thought, it was almost impossible that she was infected with Covid-19. But upon arriving at her destination, she found a surprise: the homeowner would not let her in without first having a quick coronavirus test.

Twelve tests he had purchased to test family members and acquaintances visiting his residence. The tests had been purchased for $ 22,000 from a known dentist. So Javiera agreed to take the exam without hesitation. She put her index finger to prick it and deposited the blood in a slot “of those similar to those of pregnancy,” she recalls. The puncture did not hurt, and within minutes the exam showed a red streak: negative for Covid-19. “I made him happy, because I was able to go out and he gave me greater security, although they say he has a super low probability of success,” acknowledges Javiera.

Towards the end of March there was already talk of the existence of rapid tests for Covid-19 and how they were being implemented around the world. This, because they promise to be the key tool for the return to the “new normal” that is being talked about these days. “Its main use will be to examine direct contacts of someone who has tested positive and has not developed symptoms,” then confirmed the Health Minister, Jaime Mañalich, while announcing the purchase of a million kits of these rapid tests. But not only that. It has also been said that the application of these tests could eventually serve to deliver the “discharge cards” that Mañalich mentioned a few weeks ago for people who have recovered from the disease and have been released from quarantine.

The Covid-19 rapid detection test measures the presence in the blood of antibodies generated against the disease, through a sample that is deposited in one of the cartridges for analysis. Positive, negative or invalid are the options provided by the exam. “The presence of antibodies in the blood indicates that the person had contact with the virus and, from studies done in the other coronavirus in 2003 (Sars Co-vi-1), it is presumed that the presence of the antibodies could protect the person with new Covid-19 infections, but in reality there are no certainties ”, explains the former president of the Chilean Society of Infectious Diseases (Sochinf), Mónica Lafourcade.

This test does not provide an official diagnosis for coronavirus. This was confirmed on Friday by the Undersecretary of Public Health, Paula Daza: “The only diagnostic test that confirms that a person has Covid-19 is the PCR test. And this exam has to be taken by certified professionals, in a laboratory that is certified by the ISP. There are other tests at the country level called rapid tests that sometimes confuse the community for the diagnosis. ” When analyzing only the antibodies, the method is not designed for an express use, like the one Javiera experimented with, as the conclusions can be wrong and throw false negatives. “It is not a test that serves today to make a diagnosis of Covid when the person begins with the symptoms, because the antibodies appear late from the second week after the onset of symptoms,” adds Lafourcade.

However, the antibody test would be effective for mass testing, as a surveillance tool to estimate the relative proportion of people who have had contact with the virus in different populations. Hence its worldwide and local quotation by companies and public entities.

According to Public Market records, 51 municipalities nationwide have requested this type of supplies to detect the presence of the virus, for an amount that exceeds $ 1,535 million. The municipality of Coelemu, in the Ñuble Region, leads the amount paid to buy these products, after issuing orders for 2,000 kits, valued at almost $ 24 million. And the commune of San Carlos, in the Biobío Region, is the one with the highest number of rapid examinations requested: 2,520, for an amount of $ 15 million.

The Undersecretariat of Public Health, according to the Public Market records, is another of the major buyers of these supplies. Acquired more than 70 thousand quick test kits, for an amount that is around $ 515 million.

The rise of this new market has revealed a risk that is in the sights of the authorities: the commercialization of unreliable and uncertified tests. Proof of this was what happened a few weeks ago in Spain, where the Hispanic government bought 340,000 rapid tests from a Chinese company that were defective and did not meet the required quality and reliability standards. Or in the UK, where it was recently confirmed that the detection kits they had ordered from China were not sensitive enough to detect the antibodies, as they only did so in people who were very ill. To avoid this, the Institute of Public Health (ISP) published a list with 32 manufacturers from the US, Brazil and Asian countries that are certified to sell the tests in Chile.

With all the caveats, the informal market does its thing and kits are offered online, without specifying where they come from. “There are many brands of dubious performance and that are offered in the informal market, that is a danger and should be better regulated, because it can have serious consequences,” says Monica Lafourcade.

In fact, the Municipality of Las Cabras, in the O’Higgins Region, issued in early April a purchase order to the La Casa Blanca Spa Clinical Laboratory to acquire 130 rapid tests prepared by the Chinese company Dynamiker Biotechnology, for almost $ 3 millions. However, the Asian firm is not on the list of 32 companies certified by the ISP for the sale of the rapid exams. From the laboratory they claim to be certified by the German Clinic, but the clinic denies it.

Where the efficiency of this method could be most reflected is in the testing of workers. An article published in La Tercera by academics from the Adolfo Ibáñez University and the Grupo Bios firm – linked to the scientist Pablo Valenzuela and importers of rapid tests – stated the following: when testing people in a company once or twice a week, derive The health system for those who test positive, trace the contacts of those infected and test them as well, will break the chain of infections, isolating those who are ill. They point out that applying this method, about 95% of workers could continue their work, as opposed to 58% if the company closes every time a case appears. Otherwise, if no control measure is applied, 26% of the workers would be infected.

For its part, the quick test kits have already been acquired by the mining company BHP, which spent US $ 8 million on 150,000 units. “Initially we will apply them to people with respiratory symptoms, whom we will then send for confirmation with a PCR test. This to evaluate the quality of the tests ”, says Alberto Pacheco, head of Health at BHP.

“Testing maintains a safe environment within the company. It prevents the number of cases of contagion from growing, because there are few infected people circulating, since it is detected relatively quickly ”, explains the economist Alexander Galetovic, who is part of the aforementioned group of academics. However, for the application of this method, a coordination scheme is key, such as measures of social distancing, effective compliance with quarantines and public-private collaboration. For this reason, the Ministry of Finance has held conversations with members of this group, who are advising them to return to work.

Among doctors, they are apprehensive about the idea that rapid testing be implemented massively. The WHO already warned it in early April, ensuring that its use should be limited only for clinical settings, investigating its performance and potential for diagnostic utility. Dr. Cristóbal Cuadrado, an academic at the University of Chile’s School of Public Health agrees: “We still do not know if the antibodies detected by the tests translate into effective immunity or for how long that immunity lasts. In that sense, using it as a tool to get people to work is something rushed, a bet that is not without risks ”.

For now, for the President of the Medical College, Izkia Siches, its implementation should be for epidemiological purposes only, to test asymptomatic patients, carry out quarantines or carry out cross-sectional studies. “The other countries that propose this new normality had a significant number of infected people and their healthcare network was overloaded. But here we still have a lot of susceptible people. If we can diagnose and isolate cases and contacts, we will be able to enter this normality. If that is not strengthened, the most likely thing is that we are going to open, something is going to set fire to us, we are going to have to close, and so on, ”he warns.

For experts, the best way to start using them is as a complement to PCR tests and also increase the application of this test if you have symptoms. Words, behaviors and concerns of the new normal.