Directors of the National Health Surveillance Agency (Anvisa) approved this Friday (28) the sale of Covid-19 self-tests. The tests, which can be done by the patient at home and without the help of a health professional, will be an additional tool to diagnose the coronavirus infection.
However, the decision has no immediate effect: each company interested in marketing its version of the product must apply for registration with the agency, which will analyze each request.
The measure is valid only for the so-called antigen tests (made by collecting the material at the back of the mouth and nose and looking for signs of antibodies generated by the body after infection), and does not apply to RT-PCR tests (more accurate, longer and that detects the presence of the genetic material of the coronavirus).
See questions and answers on the topic:
- What is a self-test and how does it work?
- Are self-tests available now? How much does it cost and where to buy?
- Can the self-test be used as proof of travel and/or medical certificate?
- When should the person with suspected Covid-19 take the self-test?
- Why can the self-test give a false negative?
- What is the procedure in other countries? How do people send information to the government?
- What would be the safest way to dispose of waste? Is there a chance that someone else will catch it handling the garbage?
- Is there a PCR test in self-test?
- How can self-tests help control the pandemic, in the opinion of experts?
Understand how the self-test works to detect Covid
they are a how to diagnose coronavirus in case of suspected infection.
The self-test is similar to the rapid antigen test, but can be done by laypeople at home. The kit comes with a test device, extraction plug, filter and the swab — a kind of swab used for nasal collection, the most common (see video above).
The so-called “antigen test” is able to identify the viral antigen, which is a structure of the virus that causes the body to produce an immune response against it – antibodies.
“The self-test is a tool that helps in the follow-up issue. The person can take the test to find out if they are still positive, but mainly in prevention. They can test themselves in order to avoid transmission”, explains infectious disease specialist Alberto Chebabo, president of Brazilian Society of Infectious Diseases (SBI).
2. Are self-tests already available? How much does it cost and where to buy?
Self-tests are not yet available for purchase. According to the National Health Surveillance Agency (Anvisa), each company interested in marketing its version of the product needs to apply for registration with the agency, which will analyze each request.
The sale must take place in pharmacies and establishments that can sell health products, as long as they have the health license and are regularized. About internet sales, only these establishments will be able to sell. They cannot be sold on e-commerce sites.
Companies will be able to buy self-tests and distribute them to their employees. There is no restriction on this.
About values, Anvisa hopes that they are cheaper than the current ones, made in pharmacies.
3. Can the self-test be used as proof of travel and/or medical certificate?
No. Anvisa warns that the self-test does not generate a report. “You will have information for individual use. It does not serve as proof that you do not have Covid for international travel, for example, nor will it be directly accepted by the employer for the purpose of dismissal from work. health professional”, explains the agency.
4. When should the person with suspected Covid-19 take the self-test?
You should do three to seven days after the onset of symptoms. “This is the interval that brings the best confidence in the results, according to the manufacturers”, guides microbiologist Luiz Gustavo Almeida, from the Institute of Biomedical Sciences (ICB) at the University of São Paulo (USP).
The microbiologist explains that when you come into contact with someone infected, you have to wait a few days to avoid a false negative. “If you do it the day after contact, it is very likely that the result will be negative. That’s because you don’t have enough virus in your body for the test to detect.”
5. Why can the self-test give a false negative?
Because it might not be able to detect the virus even if it’s there — especially if you don’t have symptoms of the disease.
“In the asymptomatic person, we consider that, if the person is infected, the viral load is lower and the risk of a false negative for antigen is higher. It is not the best test to do in this situation. PCR”, warns Alberto Chebabo.
- Antigen Tests: Understand Why You Could Be Infected Even If You Are Negative
Infectologist Evaldo Stanislau, director of the São Paulo Society of Infectious Diseases (SPI), advises that if the test is negative and there is suspicion of infection, the individual maintains isolation and repeats the exam between 24 and 48 hours.
6. What is the procedure in other countries? How do people send information to the government?
Depending on the country, kits are available for purchase and/or even distributed by government health agencies.
In the United States, the Centers for Disease Control and Prevention (CDC) authorizes the sale of self-tests in pharmacies as part of a comprehensive testing policy.
According to the American health organization, this is one of the many risk reduction measures adopted by the government, such as vaccination, mask use and social distancing: “Self-testing is one of several test options for Covid-19 and may be more convenient than tests done by laboratories”.
Self-tests are also authorized in Europe, but the European Center for Disease Prevention and Control (ECDC) says routine use needs to be very “well-planned and carefully implemented”.
In a document addressed to health authorities, the agency stated that, before implementing self-examinations, it is necessary to analyze the prevalence of the disease (number of cases) and the scenario in which they will be used – such as, for example, to test the population. general or for specific groups or situations.
One of the warning points addressed is the chance of underreporting of cases, as the information would not reach the government through the health system: “Transferring the responsibility of reporting test results from health professionals and laboratories to individuals can lead to underreporting and make measures like contract tracking and quarantine even more challenging.”
In the United Kingdom, Covid self-tests are distributed by the public health system. Brits can pick them up at pharmacies or order them online for delivery by post.
With the result in hand, the British government’s recommendation is that users report the infection over the internet to Organs responsible bodies. In other countries, such as Australia and Canada, it is also possible to obtain the tests for free from the public health system.
7. What would be the safest way to dispose of waste? Is there a chance that someone else will catch it handling the garbage?
Some self-test manufacturers recommend that you throw them in the regular trash.
For Luiz Gustavo Almeida, the ideal would be to discard it in places indicated for this material, whether in pharmacies or public places. However, the risk of contamination from the self-test is very low.
“I don’t know of any case [de contaminação]. I searched the literature, but did not see any reported cases. The self-test has little material. It’s enough to detect, but it will stay there for 15 minutes, in solutions and probably the viral sample will lose activity. It is very difficult for someone to contaminate themselves with this material. But, in any case, the disposal should be treated as biological waste”, he explains.
The director of the Paulista Society of Infectious Diseases (SPI) agrees and believes that disposal should not be a limiting factor for this type of examination.
“The virus does not have the ability to resist the natural environment for so long. This type of test uses respiratory secretions. The heat and environment itself take care of drying out all viral particles and will quickly make them free from any risk. is to pack it in a thick plastic bag and identify it as infectious”, says Stanislau.
8. Is there a PCR test in self-test?
No. The PCR test involves several enzymatic reactions and requires more sophisticated equipment, available in large laboratories.
9. How can self-tests help control the pandemic, in the opinion of experts?
For the experts, self-test is relevant when we have many positive cases somewhere, as is happening in Brazil.
“It would be a good indicator, even with limitations [coleta errada, falso negativo]. It would serve as an alert and it would be important to have an idea, a monitoring of the real situation”, says Luiz Gustavo Almeida.
“The self-test is important because we have the issue of the person leaving the house to test and face hours in line. The person can arrive without a virus and leave infected. The self-test also brings agility. If the person tests positive, he does not leave the house and informs the family. I also believe that it will be important in the post-peak period of the pandemic. We measured community transmission through hospitalization rate, new cases, deaths and percentage of positivity. By regularly testing the population, we will have real and concrete data on community transmission to define control measures”, says Stanislau.
However, in Luiz Gustavo’s view, it is necessary to have a system to report positive cases. “For public policy purposes, if you don’t have an information system, it won’t be worth doing the self-test”, he adds.
For Stanislau, notification is important, but at this time of health emergency it is necessary to test. “If she tests and sees that it is positive, she will not leave the house and will map her contacts. One experience we have is that people believe in tests. If it is positive, they respect it more”, she says.