How is Covid-19’s national mass testing strategy doing? For now, just local

How is Covid-19’s national mass testing strategy doing? For now, just local
How is Covid-19’s national mass testing strategy doing? For now, just local

“Your Covid-19 test gave an undetectable result.” The message arrives on the phone at 5:05 pm, exactly 15 minutes after we left the testing center at Covid-19 of the Nifo pharmacy in Algés, one of seven that are already on the list of pharmacies that adhere to the City Council’s free mass testing program de Oeiras, which started yesterday, Monday 5 April.

The visit was quick and without crossings with other users, although Arshad Gafar, the health service professional, ensured that the day was busier than usual. “We were testing ten people a day and today there were 17, seven of whom were under the protocol with the Chamber”, he reveals. To be able to perform a rapid antigen test again, it will be necessary to wait 14 days, as each resident in the municipality has the right to do two free tests per month. In addition to pharmacies, the municipality also announced that it will be possible to carry out tests on an itinerant Mobile Unit, which will be placed in strategic locations in the municipality.

Like Oeiras, the Lisbon City Council also started a free mass testing plan on March 31st. Residents, over the age of 16, from parishes with more than 120 new cases per 100 thousand inhabitants in 14 days, can schedule a rapid antigen test by telephone in one of the more than 100 pharmacies in the municipality that have already joined the plan.

The earlier we identify cases of infection, the greater our ability to resolve any transmission chains

ricardo mexia – president of the national association of public health doctors

For now, only 10 parishes are contemplated (Ajuda, Alvalade, Arroios, Estrela, Marvila, Olivais, São Vicente, Santa Clara, Santa Maria Maior and Santo António), but the list will be updated every 15 days, according to the evolution of Covid-19 numbers. Also in Lisbon, each resident is entitled to two tests per month.

In Portimão, since March 23, a mass testing operation has been taking place, following an outbreak of Covid-19 related to the civil construction sector. After four days of massive testing at the Portimão Arena drive thru and three days of proximity testing in the parishes of Figueira, Mexilhoeira Grande, Ladeira do Vau and Montes de Alvor, the municipality adopted a sectoral strategy that encompasses civil construction, markets, municipal services, civil protection agents, taxi drivers, bakeries, home support companies, private security, fishermen and commerce.

Early detection of cases of infection to better control the pandemic is the main objective pointed out by municipalities that have already launched massive testing programs, and also defended by specialists. Ricardo Mexia, President of the National Association of Public Health Doctors, assures that testing is essential, both in symptomatic and asymptomatic people, because “the earlier we identify cases of infection, the greater our ability to resolve any transmission chains that arise and reduce the potential for the spread of the disease ”.

Waiting for a strategy nationall

Since February, the Minister of Health, Marta Temido, has expressed the desire to test the country on a large scale, free of charge and without medical prescription. On March 18, a task force was created, precisely to elaborate an Operationalization Plan for the Health Strategy. Testing in Portugal, but the group, coordinated by Fernando Almeida, president of the Directing Council of the National Institute of Health Doctor Ricardo Jorge (INSA), does not seem to have a set date for presenting the plan yet, indicating only that it will be in the coming weeks.

Still, quoted by the newspaper Public on March 26, Francisco Almeida assured that, in addition to the 1.5 million screening tests already available in the country’s strategic reserve, “12 to 13 million more tests are on the way, of which between 750 thousand and one million already arrive within of days ”. That same morning, at a press conference, the Minister of State and Presidency Mariana Vieira da Silva confirmed “The strategy of very significant extension of the tests”, materialized in the definition of strategies so that “in places where the incidence exceeds 120 [novos casos por 100 mil habitantes] there are tests in a more widespread way ”.

At the time of publication of this article, the Ministry of Health had not yet answered the questions from VISÃO, namely what is the expected date for the presentation of the program, what types of tests will be considered (PCR, antigen or self-tests), if there will be places of tests created specifically for this purpose, whether the costs of testing are borne by each municipality or will be borne by the Executive and how many free tests per month citizens will have access to.

IN VISION, Ricardo Mexia underlined some of the suggestions, which he had already given on March 23, during the meeting of specialists from Infarmed, regarding the best way to proceed with mass testing. “It must be guided by several factors and it may make sense to reinforce it with populations who are more exposed, in healthcare or public transport, or who are more vulnerable, such as seasonal workers, migrants and homeless people.”

The danger of hiding positive results

The greatest fear of specialists is related to the monitoring and reliability of the results of the tests that will be carried out. If the local programs in Oeiras and Lisbon are based on a protocol with the National Pharmacy Association, allowing all results to be automatically inserted into SINAVE, the national epidemiological surveillance system, and shared with public health teams, there is no guarantee that this will be replicated. the measures to be defined by the task force.

If the use of so-called self-tests, sold in pharmacies and made at home, is admitted, the epidemiologist Manuel Carmo Gomes fears that “there will be a large percentage of rapid tests done without the supervision of health professionals, compromising the reliability of the results”.

For Ricardo Mexia “it is important that citizens do not draw conclusions that these tests do not allow to remove and avoid excessive interpretation”, not least because “a negative result of one of these tests is not a carte blanche so that people can do things that, on the other hand, way, they wouldn’t do it ”.

Both experts agree that, in these cases, the existence of an efficient system, which allows the recording of results to be streamlined, will be essential. Manuel Carmo Gomes even defends that the communication of the results of this type of tests should have a separate system. “Thus, we could easily separate the accounts of the percentage of positives from this universe of tests from the accounts of the percentage of positives of the tests done with professional supervision”.

The epidemiologist also says that he is afraid that whoever has positive results in the self-tests, may not even report them to the SNS24 line. “The ideal would be for mass testing to always be carried out in a pharmacy or health center, where there is the guarantee of a correct monitoring of the results”, he concludes.

What are the main risks of mass testing?

The obvious answer, as Ricardo Mexia points out, would be none. “The more you test, the more new cases are identified early,” says the public health doctor. But there is a risk that negative results will infuse the sensation in people who “have a carte blanche to do what they want”. Above all, because there can also be false negatives and false positives, but we go in parts.

Manuel Carmo Gomes admits that rapid antigen tests performed by health professionals, although ideal for mass testing strategies because they are fast, inexpensive and likely to be carried out frequently, can give false negatives. As they are less sensitive than diagnostic PCR tests, they may not detect the presence of viruses if the person has been infected for less than 48 hours and has a very low viral load in the nasopharynx.

“But, unlike PCR, these tests can be done once, ideally twice a week, that’s the good thing,” says Carmo Gomes. “Even if the test does not identify anything the first time, two days later, it already detects the infection, when the person is really contagious and able to transmit the disease”, the specialist also assures

As for false positives, Manuel Carmo Gomes explains, “antigen tests are not 100% specific and can identify a coronavirus other than SARS-CoV2, resulting in a positive result”. In these cases, “in order not to isolate people at home who do not need it”, the epidemiologist says that the results have to be confirmed with a PCR test, not least because, as Ricardo Mexia points out, such confirmation implies a series of health consequences from isolation at home to the need to respond to an epidemiological survey.

The interval between two rapid tests should be a maximum of one week and what is recommended is twice a week ”.

manuel carmo gomes – epidemiologist

As for the time interval that must exist between two rapid antigen tests, Ricardo Mexia argues that it depends a lot on the epidemiological situation and awaits what will be decided by the task force. Manuel Carmo Gomes, on the other hand, considers that, for example, 14 days are too many. “I advocate that it be a maximum of one week, but what is recommended is twice a week”.

Majority of students excluded of mass testing

If most of the country is waiting for indications from the task force, mass testing in schools started as early as January 20 and intensified as of March 16. In the four days following the reopening of daycare centers, pre-school and 1st cycle schools, more than 82 thousand tests were carried out on teaching and non-teaching workers in the public and private sectors. In the remaining levels of education, the screening starts between today and runs until April 9, for the 2nd and 3rd cycles, and from 19 to 23, for the secondary.

In a statement, the Ministry of Education ensures that all teaching and non-teaching staff, as well as all workers in Animation and Family Support Activities (AAAF) in Pre-School Education, Curriculum Enrichment Activities (AEC) and Education Component Family Support (CAF) in the 1st cycle of Basic Education in municipalities with an incidence rate greater than 120 cases per 100 thousand inhabitants in the last 14 days, will be tested. However, with the exception of Secondary Education, testing of students is not foreseen.

With the exception of Secondary Education, testing of students is not foreseen

“As far as we know, in terms of attack rate, that is, the likelihood of people being infected, age is not very relevant”, says Manuel Carmo Gomes, who warns of the importance of also testing students, including those in the first class cycle. “Although they often do not manifest symptoms, they can be infected, spreading the infection among themselves, without realizing it, and then taking it home”. The idea of ​​rapid tests is, in the words of the specialist, “to make a screening general population repeatedly ”and, for this reason,“ everyone with the capacity to infect, whether employees, teachers or students, should be tested at least once a week ”.

According to a joint guidance from the General Directorate of Health, the Social Security Institute and the General Directorate of School Establishments, published in March, tests in daycare centers and schools will be carried out at 28-day intervals, except between the first and the second (14 days), and this interval can be shortened to 14 or seven days, depending on the number of cases identified in the tests performed.

Everyone with the ability to infect, whether employees, teachers or students, should be tested at least once a week

manuel carmo gomes – epidemiologist

Despite considering the initiative to praise, Carmo Gomes believes that the periodicity of testing with antigen tests should be weekly and alert, “it is useless to do these tests only on the first day of classes, because a person who has been infected on that day or the previous day you can test negative and start infecting a lot of people a few days later ”.

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