Health causes blackout of Covid cases when changing notification rule

Due to a change in the registration system of positive cases of infection by Sars-CoV-2, the country has had a blackout of mild symptomatic cases of Covid since September.

The Ministry of Health started to require, in August, the inclusion of the lot number and manufacturer of the so-called antigen tests in health systems for the notification of cases on the e-SUS Notifica platform.

As a result, the number of positive and negative results of these tests fell sharply, which may represent underreporting of coronavirus cases across the country.

The rule does not affect notifications of severe acute respiratory syndrome (Srag), which use another system, the Sivep-Gripe, where admissions and deaths are also notified. The effect is mainly on mild symptomatic cases and may help to understand coronavirus transmission.

Tracking these indices is strategic for taking measures against the spread of Covid. Amid the arrival of the “micron” variant —potentially more transmissible, but whose real risk is still poorly understood by scientists—, understanding whether Brazil will or will not experience a high number of cases is fundamental.

Numbers are also essential for planning large events, such as Carnival and New Year’s Eve parties. Until this Saturday (4), at least 24 capitals had decided not to celebrate New Year’s Eve. Most of them canceled the celebrations for fear of the omicron variant.

Critically ill patients are treated in hospitals, where the RT-PCR test is collected. On the other hand, mild symptomatic cases, or even people who are suspected of having Covid because they have had contact with other infected people, are often tested using the faster antigen-type test.

The two tests look for the RNA of the virus in the body through a nasal swab (swab). The difference is that the antigen test uses a card similar to diabetes exams that gives the result in 15 minutes. RT-PCR needs to be performed in a laboratory and can take up to 12 hours to show a result.

The abrupt drop in notification meant that the positivity of the two types of tests in the public network, which went together until August 2021 —that is, if the positive RT-PCR tests rose, the antigen type also increased — to suffer a abrupt drop from mid-September.

Data collected from the e-SUS platform and made available on the MonitoraCovid-19 website, linked to Fiocruz (Oswaldo Cruz Foundation), show this drop in tests as of August.

“This sudden change by the Ministry of Health of the lot and manufacturer’s requirement made many health services stop reporting the antigen tests with both negative and especially positive results”, says infectologist and researcher at Fiocruz, Julio Croda.

“So the system that was already flawed, unstable and unreliable, with this change, became even more complicated”, he adds.

Sought, the Ministry of Health did not comment on the changes in the platform.

However, despite the blackout of data, it is possible to observe that the pandemic is slowing down in Brazil. Last Tuesday (30), for example, Brazil completed a month with a moving average of deaths per Covid below 300.

Before this 30-day period, this level had only been reached in April 2020, still at the beginning of the pandemic.

The reduction is very likely a reflection of the advance in vaccination, which also leads to a decrease in hospitalizations and deaths.

“Without a doubt we are seeing a decrease in coronavirus transmission and pandemic control because the moving average of deaths continues to fall and has reached this stable level close to 200 deaths per day, but the number of cases, from an epidemiological point of view, we do not know at that moment for Brazil”, evaluates the Fiocruz researcher.

For Croda, although the numbers of hospitalizations and deaths are more important for reading the current moment of the pandemic, the underreporting of cases makes it impossible to monitor what will happen after the Christmas and New Year period.

“If we follow what is happening in Europe and after the holiday season there is an increase in transmission, it is likely that the country will be surprised by a sudden increase in hospitalizations, which may be too late to propose planning measures as the opening of beds”, he says.

The current blackout of data on symptomatic and mild cases clashes with what was observed throughout the pandemic, when it was already known that the e-SUS notification system had instability problems and notification delays.

“In Brazil there was never an effective policy for extensive testing, but in 2021 the offer of tests was slightly expanded, with antigen tests, which many states and municipalities bought”, he assesses.

The federal government changed its strategy for seeking new Covid cases in May this year, when it announced the purchase of antigen-type tests.

The Minister of Health, Marcelo Queiroga, launched a national testing program, which aimed to carry out up to 26.6 million per month. The strategy, however, never got off the ground.

In addition to the lot number and manufacturer requirement, e-SUS Notifica has been showing a lot of instability in recent months.

Croda points out that monitoring symptomatic infections caused by the disease, at a time when vaccine coverage is increasing, could even help to identify symptomatic cases of the so-called vaccine escapes —a risk in the face of omicron — and to calculate the effectiveness of vaccines in real life.