Rates of respiratory infections caused by respiratory syncytial virus (RSV), influenza and covid-19 continued to decline in early February after taking a strong toll on the country this winter, leading to More than 5,672 people died All reasons for the period December 25 to January 21 compared to the previous year period.
This is confirmed by the latest weekly report issued by the Surveillance System for Acute Respiratory Infections (SiVIRA) of the Carlos III Health Institute (corresponding to the days between February 5 and 11).Document shows incidence of seasonal flu will be Return to normal value Although it has caused The fatality rate of hospitalized patients is 6.6% The 2023-2024 season started last October.
context. The peak incidence of respiratory infections this winter occurred in the last week of 2023, with influenza being more intense, with 46% of positive samples at that time.
- In order to prevent the increase in the number of infections, the Ministry of Health announced that starting from January 10, the use of masks will be mandatory in hospitals and health centers in all autonomous regions. However, two weeks later, when the incidence in the population began to decline, the measure became a recommendation.
Incidences of respiratory infections such as influenza are beginning to decline
The latest report prepared by SiVIRA reflects a decrease in the epidemiological incidence of the three main respiratory infections affecting the Spanish population this winter:
influenza. Between February 5 and 11, influenza incidence rates across the country declined across all age groups, marking a decline in influenza incidence rates across the country. when the epidemic ends The outbreak of the winter seasonal influenza wave is high in intensity compared with the past two seasons and compared with other respiratory infections.
- In terms of severity, since the start of the 2023-2024 season, 34.9% of cases hospitalized with influenza developed pneumonia, 5.5% were admitted to the intensive care unit, and 6.6% died.
Coronavirus disease. Covid-19 cases in primary care have fallen for a fifth week in a row, with a higher proportion among children under one year old. The number of hospitalized patients has also declined, with the hospitalization rate for all ages at 0.9 cases per 100,000 residents, except for patients between 65 and 79 years old, where five times the rate was recorded.
- Overall data shows that since the start of the quarter, 32.2% of cases hospitalized with covid-19 have developed pneumonia, 3.5% have been admitted to the ICU, and 8.3% have died, similar ranges to previous quarters.
VRS. For its part, RSV infection rates show a gradually decreasing trend in all age groups, with the exception of adults aged 45 to 64 years treated in primary care, where the incidence rate is 23.5 cases per 100,000 inhabitants.
- Looking at data collected since October, among hospitalized cases with RSV infection, the pneumonia rate was 22.1%, the ICU admission rate was 10.3%, and the mortality rate was 3.5%, similar to the ranges seen in previous quarters.
The “epidemic period” of respiratory infections such as influenza reaches its peak in winter
Susana Monge, researcher at the National Center of Epidemiology of the Carlos III Health Institute, explained to Newtral.es that respiratory viruses such as influenza have their epidemic period between November and March, reaching “the greatest intensity of transmission” between November and March Peak”. It falls below the threshold after 4-6 weeks in late December and early February. ”
This winter’s seasonal epidemic is coming to an end as SiVIRA confirms a decline in influenza incidence in its latest report. However, experts note that “influenza viruses continue to circulate sporadicly, associated with baseline influenza incidence,” so “we cannot safely rule out the possibility of a new wave of influenza epidemics this season.”
Why are there more flu cases this season than in previous years?
Researchers at the National Epidemiology Center said that of the three viruses that cause acute respiratory infections monitored by the system, “only influenza spreads more intensely than in the previous two seasons,” while covid-19 spreads at the same rate as the previous two seasons. Seasons are similar. Last winter, RSV spread to a lesser extent.
The increase in influenza incidence “may be determined by the spread of other viruses and the ability of each virus to displace the spread of another virus and find opportunities for its expansion.”
On the other hand, it is also possible that influenza epidemics “will be more severe over time as more susceptible people accumulate who are not infected by Covid-19 pandemic control measures”. However, “it is difficult to compare with pre-pandemic seasons because surveillance systems have changed, which is a limitation in comparing before and now,” he added.
Vaccination is ‘fundamental preventive measure’ against respiratory infections, experts say
For experts, vaccination is an “essential preventive measure” against the rise in acute respiratory infections. In this sense, it explains the recommendations for vaccination against influenza and covid-19, among others, for all people at high risk of severe disease, mainly people over 60 years old, pregnant women and people living in closed institutions.
The targets for influenza and covid-19 vaccination are to reach or exceed 75% vaccination coverage among older people, health and social care workers, and 60% or above among pregnant women and high-risk groups. Despite this, Monges noted that annual vaccination targets “have never been met” because some of the recommended groups “decided not to participate.”
In this regard, the researchers recalled the importance of vaccines to protect “the impact of these viruses on population health and health systems from saturation at the peak of the epidemic.”
source
Carlos III Health Institute Surveillance System for Acute Respiratory Infections (SiVIRA)
Susana Monge, researcher at the National Center of Epidemiology, Carlos III Institute of Health