ROMA. While some viruses appear to have disappeared from circulation and others have seen a slight off-season recovery, still others are poised to return with a rebound in the coming months. With the relaxation of the restrictions against Covid-19, in fact, other respiratory viruses, which remained muted last year, could manifest themselves with peaks of contagion in the coming cold months. To worry doctors and pediatricians are in particular the flu and the respiratory syncytial virus, known for bronchiolitis in infants but which does not spare even in the elderly and adults.
While rhinoviruses continued to spread even during the pandemic, “perhaps because they are less susceptible to measures such as disinfection and hand washing”, other winter viruses, such as human coronaviruses and parainfluenza viruses, were at very low levels in winter 2020, but they began to rise to pre-pandemic levels in the spring of 2021. Response measures to Sars-Cov-2, coupled with vaccines, appear to have suppressed measles, pneumonia and meningitis and the flu virus. But they will return with a rebound in the coming months, facilitated by the cold.
Seasonal flu, warns an article published on the Nature website, “causes 290,000-650,000 deaths a year worldwide, and in 2021 it has practically vanished. But most experts agree that it will recover. “, perhaps” fiercely “, as travel restrictions and interventions to curb Sars-Cov-2, such as wearing a mask and maintaining distance, will decrease. This is confirmed by Fabrizio Pregliasco, a virologist at the University of Milan and medical director of Irccs Galeazzi in Milan. “There are 262 respiratory viruses, from the rhinovirus, which causes a simple stuffy nose, to the metapneumovirus, which gives symptoms similar to Covid. These viruses form a complex ecosystem, which has been altered by the circulation of Covid and by the measures to contain it. Now that thanks the vaccine has resumed many indoor activities, including school and work, as well as the movement of people, the flu will also regain its footing. This is why we must vaccinate the elderly and those at risk in particular, such as asthmatics “.
Streptococcus and pneumococcus will also resume circulation, as well as the syncytial virus (Vrs). Responsible for about 5% of deaths in children under 5, the syncytial virus recalls the article in Nature, “it saw infections at historic lows during the pandemic in all countries, but then started to trace back in April 2021. “: Off-season peaks were observed in the US, Japan, Australia and the Netherlands. “This is an underestimated virus – recalls Fabio Midulla, president of the Italian Society for Child Respiratory Diseases (Simri) – and for which we still do not have approved vaccines. In the elderly it can exacerbate Bpco and lead to interstitial pneumonia. In children it can cause asthmatic bronchitis. and bronchiolitis in infants requiring intensive care. The first concern is that it circulates with new variants. The second is that, since it has not circulated for nearly two years, pregnant mothers have no antibodies to transmit to newborns. ” The hope, concludes Midulla, is that Covid has taught simple rules, such as not to return to the community as soon as it fades but to stay a few days in convalescence “.