Later than usual, probably due to the persistence of high temperatures, the incidence of acute respiratory infections as a whole is in full ascendancy, a trend that, according to health authorities, indicates “the beginning of the waves “autumn winter epidemics”. While health centers prepare for an increase in cases, only a quarter of Catalonia's vulnerable population has been vaccinated against flu and covid, a significantly lower percentage than last year at this point.
In the last two weeks, the respiratory syncytial virus (RSV) and flu curves have skyrocketed. Covid, for its part, maintains a more stable behavior, according to data from the Information System for Infection Surveillance in Catalonia (Sivic). “RSV has been delayed a couple of weeks, but we already see that it is presenting a change in trend that is beginning to resemble epidemic phases,” explains Jacobo Mendioroz, deputy director general of Public Health Surveillance and Emergency Response.
Normally, he specifies, the rise of the respiratory syncytial virus precedes that of the flu by two weeks, but this season they have started the rise at the same time and have been climbing for two weeks. The Department of Health estimates, according to previous exercises, that the epidemic peak will take place within two or three weeks, but there are unknowns.
Unknowns, for example, about the behavior of covid. There has never been a triple circulation, because some viruses prevail over others. At the height of Covid, the flu practically disappeared from the scene for two seasons. “At the moment it is difficult to interpret the behavior of the covid, which has been oscillating for a few weeks, and although it presents a slight increase, I would say that it is stable,” analyzes Mendioroz: “We will see if we will have a triple circulation of viruses for the first time, which which I highly doubt, but it is not ruled out. “We are in somewhat unknown territory.” The evolution of this week and the following is being closely observed due to the possibility of a triple wave.
What would be its consequences? If Covid and the flu had the same intensity, the impact on the health system would be equivalent to twice that of a wave of flu, with a similar amount of admissions and morbidity, experts maintain.
One of the indicators of the beginning of the flu and RSV waves is the number of infections of people between 15 and 44 years old, the segment that has the most interaction and mobility. “After a couple of weeks it reaches the most vulnerable population,” says Mendioroz. Therefore, it is important that the population and the healthcare system are prepared: consultations and admissions will increase.
Of the 3,144 flu diagnoses made in Catalonia in week 46, from November 13 to 19 (2,354 in the previous season), nearly half (1,438) correspond to patients between 15 and 44 years old. The percentage of positive samples has skyrocketed in the last two weeks.
Another of the unknowns of the season is the effect of vaccinations on minors. For the first time this fall, children between 6 and 59 months of age have begun to be immunized against the flu, in addition to people over 60 years of age and the population with risk conditions as vaccinable segments of the population. However, the percentage of families that have opted for this protection is low (17% up to 4 years old). The immunization of babies up to 6 months against the respiratory syncytial virus (RSV) also debuted this fall, one of the main causes of hospitalization in children under 5 years of age due to the bronchiolitis and pneumonia it causes.
Health centers are beginning to notice bronchiolitis. The last week analyzed, 680 cases were diagnosed in Catalonia – half of them corresponding to babies under one year old – when two weeks ago there were 413. The curve points clearly upwards, with quite a delay compared to the previous season, when It reached its peak in week 47, the current week, with 1,872 diagnoses, and then the curve began to decline.
Now that the indicators are beginning to rise announcing epidemic phases, “it is a good time to start getting vaccinated against flu and covid if it has not been done,” says Mendioroz. “If any vulnerable person was in doubt because it was hot, this has changed this week, and there is still time to acquire immunity, for which it has to come in about two weeks,” he adds.
In fact, a relaxation is observed among the groups susceptible to immunization: those over 60 years of age and people with vulnerability factors. Only 26.62% of the candidates have been immunized against the flu, the lowest percentage in recent years (last year at this time a rate of 33.22% was recorded and the maximum, 43%, was reached at end of February). Those over 80 years of age are 55% vaccinated.
Regarding covid, the vaccine coverage rate of the susceptible population remains at 22.59%, when a year ago it stood at 33.06% and reached the ceiling (47%) in February. Also in this case, the group of people over 80 years of age is the most immunized (45%). There are currently 342 patients hospitalized for covid in Catalonia. It is the lowest number in the last four seasons in week 46, but it is the highest in the last six weeks. On the other hand, there are 10 people seriously admitted to the Catalan ICUs due to the coronavirus.
