Spain enters epidemic phase for acute respiratory infections driven by rising COVID-19 cases

Surge in primary care infections

National surveillance data for week 39 (21–27 September 2026) showed acute respiratory infection rates reaching between 476.7 and 478.2 cases per 100,000 inhabitants, surpassing the national epidemic threshold. Primary care health centres recorded SARS-CoV-2 as the primary pathogen behind respiratory illnesses, with test positivity reaching 27.2%, up from 26.8% the preceding week. In contrast, influenza accounted for 4.1% of tested respiratory cases, while respiratory syncytial virus accounted for 0.2%. Medical specialists noted that while consultations in primary care have climbed, hospital capacity has not experienced severe strain. Isabel Jimeno, head of the vaccine group at the Spanish Society of General and Family Physicians, described the operational situation across outpatient services.

An increase is visible in primary care. Fortunately, regarding hospital care and admissions, the situation is not alarming.

Hospital impact and the dominant XFG variant

Severe acute respiratory infection hospitalisations stood at 9.2 cases per 100,000 inhabitants during the final week of September. Among those admitted to hospitals with severe respiratory illness, 21.0% tested positive for SARS-CoV-2, an increase from 15.3% reported in the prior week. The overall Covid-specific hospital admission rate rose from 1.1 to 1.7 cases per 100,000 inhabitants. Genetic surveillance identified the XFG lineage as the dominant strain, accounting for approximately 55% of analyzed Covid cases in Spain. Both the World Health Organization and the European Centre for Disease Prevention and Control assessed that XFG exhibits immune evasion similar to prior lineages and does not generate more severe disease symptoms.

The real pressure on the healthcare system and hospitals remains at low-intensity levels for now.

Age demographics and transmission patterns

The rise in transmission has concentrated heavily among populations over 70 years old and children under five years old. Regional surveillance registered an overall incidence of 629 cases per 100,000 inhabitants among individuals under 15 years old, alongside higher emergency department visits for infants and toddlers. José María Eiros, director of the National Influenza Centre of Valladolid, observed that SARS-CoV-2 has exhibited fluctuating circulation across the year rather than following a strictly seasonal winter schedule. Transmission rates among younger segments of the population began climbing eight weeks prior to late September, influenced by the resumption of school classes and lower past vaccination coverage in younger demographics.

Research on non-seasonal patterns and vaccination timing

A research atlas examining 18 respiratory pathogens between 2022 and 2025 by public health researchers in Catalonia found that SARS-CoV-2 established peak incidence during spring and summer months rather than winter. This non-seasonal circulation pattern created a structural mismatch with regional autumn vaccination campaigns, which administer Covid-19 boosters simultaneously with annual flu shots. Vaccination coverage in Spain currently stands at 65% for influenza and 50% for coronavirus among individuals aged 65 and older. Health officials are reviewing whether scheduling adjustments could improve protection before peak transmission windows occur. Jacobo Mendioroz, deputy director general of surveillance and public health in Catalonia, addressed the policy dilemma.

We are immunizing the at-risk population in autumn, when the epidemic waves of the virus have already passed, and not before, as would be desirable. This work puts on the table the possibility that it may be necessary to adjust the planning of vaccination campaigns and recommendations.