The closure of schools and the associated decline in mobility, as well as the government’s more restrictive measures from mid-January, contributed to a faster decline in the transmission rate of the SARS-CoV-2 virus, making the effects of the current restriction very strong near the Effect achieved with the restriction introduced in March and April last year. Within a week, the transmission of the virus could be reduced by 35% to 40%. It’s early days to relax, but this better adherence to measures is starting to have an impact on Covid-19 numbers. Although hospital stays and deaths remain high.
“In order to evaluate a containment, it is important to measure its effect. The effectiveness of a restriction is seen in the decrease in the portability rate. This rate is the product of two elements: the contact rate – mainly represented by mobility – and the probability of transmission – represented by the properties of the virus and the protective barriers we use, ”explains PUBLIC Pedro Simões Coelho, coordinator of the Covid19 Insights project, an initiative of NOVA IMS and COTEC.
To measure the impact of the current restriction, the reference was given as the average rate of decline in the transmittability of the virus in March and April last year. “We estimate that at the beginning of this restriction, this decrease in the transmission of the virus occurred at a rate equal to 30% of the rate achieved in March and April. In other words, it was 30% of the effect that was achieved in the first delivery, ”says the specialist, referring to the period from the second week of January until schools close. From that date on, “this effect began and gradually increased, and at this point we estimate that the effect of this restriction is about 90% of the March / April effect”.
What has changed to achieve this result, despite the fact that the mobility that people have assumed has already decreased a bit since the beginning of January in anticipation of the restriction decided by the government? “Up until January 17th, the workplace presence was still very strong. Compared to the reference level – average mobility in January and February 2020 when there was no pandemic – there was already a certain decrease from -11% to -26%, but now the decrease is over 40%, “explains first.
“From the week that the State of Emergency measures were stepped up, there was a greater decrease in presence in workplaces, when using public transport and when traveling to retail and catering areas. Schools carry a lot of mobility with them. Only then did we actually move from reducing the transfer rate by 30% to 40% to a situation where the decline is almost the same as in March. It rarely happens that we have a situation where there is such an immediate effect. “Says.
To better understand the effect, experts compared the decrease in the rate of transmission of the virus between midweek, which started January 11th and ended on 15th, and midweek, which started January 25th and ended on January 29th. “The change in containment measures, particularly those related to the closure of classroom activities, and the resulting decrease in mobility, have helped reduce virus communicability by 35% to 40% in one week.”
The peak prevalence is close
This change now allows for more favorable estimates than two weeks ago. Therefore, the peak of prevalence is expected today with around 182,000 active cases. That number was slated to drop to 160,000 on February 7th. For this day, too, the scenarios indicate the existence of 5900 people with hospital covid, of whom 825 are in intensive care units. The maximum number of hospitalizations was reached on the first day and the maximum number in the intensive care unit is expected to be reached by the end of the week. The deaths peaked on January 30, with around 300 deaths per day.
However, the country is still a long way from breathing relief, even though the Rt (risk of transmission) is slightly below 1. It is estimated that this should only drop below 0.8 in the second half of this month and it will for this reason that the safety limit of 5000 new daily cases should be reached. “The value of 50 new cases per 100,000 population has been used by many as a barrier below which it is possible to achieve adequate traceability of the cases and to identify the transmission chains. And that’s why we have to do it as soon as possible, ”defends Pedro Simões Coelho.
The President of the Scientific Council of NOVA IMS also notes that the estimated number of hospital stays, especially in the intensive care unit, shows how close the National Health Service (SNS) is to its maximum capacity, using the same criteria as in previous stages According to estimates, the pandemic would indicate a higher number of patients with around 200 patients in the intensive care unit.
“This is one of the reasons why the restriction has to continue in this strict manner for some time. It is important to maintain or intensify [a queda da transmissibilidade] for some time to avoid this situation of rupture and to prevent this excess of mortality from continuing, ”he affirms that it will be possible to guess gradually when there is the ability to control chains of transmission and lower numbers . But always evaluate these effects so that a new growth of infections can be stopped.