Maybe this could happen. But, unfortunately, we have outbreaks of dengue fever every year in Brazil; dengue and its symptoms are very known to Brazil already. Although the symptoms seem to be almost the same to covid-19 — when using the latest CDC list  to compare — there is one that makes a large difference: the shortness of breath. This is only present in covid-19.
I agree that this year will be specially difficult due to the doubling with covid-19. In several places, the Brazilian government puts the responsibility of dengue fever into the population — you have to take care, clean your places, get rid of the mosquito… — and people in Brazil seem not to care anymore.
On the covid-19 side, people are not being tested enough — or caring as they should, in several places. The article says that Brazil is making every effort to keep the number of cases from rising; I kindly disagree. The government and the people could do a lot more; however, people are dying in their rush of “living”, and the government doesn’t seem to care — even demanding and encouraging people to get “back to normal”.
I found another comment on this, made in May, from one of the authors .