Co-infection with influenza could suppress replication of SARS-CoV-2
A study yesterday in the Journal of Virology suggests that, while co-infection with influenza A and SARS-CoV-2 does not change the trajectory of influenza A, contracting influenza A first could suppress any COVID-19 infection caused by SARS-CoV-2.
The study is based on experiments conducted in cultured cells and golden hamsters, and has yet to be replicated in humans. However, researchers say the findings could have implications for the upcoming cold and flu season, which will bring more co-circulating influenza and COVID-19 viruses.
"This study could be used as an example of how an immune response to something unrelated can provide protection against SARS-CoV-2," said senior study author Benjamin R. tenOever, PhD, in a press release from the American Society of Microbiology (ASM), which publishes the journal.
In the hamster experiments, animals infected with influenza A virus (IAV) 3 days prior to infection with SARS-CoV-2 generated lower SARS-CoV-2 virus titers than did animals that were infected solely with SARS-CoV-2 at each time point, the authors said. Time points were days 1, 3, 5, 7, and 14 post-infection.
When the experiment was reversed, an initial SARS-CoV-2 infection did not alter the severity of influenza A infection.
"We find that IAV interferes with SARS-CoV-2 replication in the lung, even more than 1 week after IAV clearance. In contrast, IAV exhibited robust replication in the respiratory tract of hamsters, regardless of the presence of SARS-CoV-2," the authors concluded. "These data suggest the presence of factors intrinsic to or induced by IAV that may restrict the growth of SARS-CoV-2, but it remains unclear whether this effect plays a role in disease severity."
Jul 12 J Virol study
Jul 12 ASM press release
Global unexplained hepatitis cases in kids top 1,000; WHO launches survey
The World Health Organization (WHO) said yesterday in an update on unexplained hepatitis in children that 1,010 probable cases have been reported, 22 of them fatal, from 35 countries.
The new total reflects 90 new cases and 4 new deaths since the agency' last update on Jun 24. Since then, Luxembourg and Costa Rica have reported their first cases.
The pace of new cases has slowed over the past month, but the WHO said the trend is hard to interpret, given the delay in reporting cases and limited surveillance in a number of countries. Adenovirus is still the most frequently detected pathogen, but limited adenovirus surveillance in most countries makes it hard to assess whether rates are higher than expected. Most cases don't have epidemiologic links, but some have been reported in Scotland and the Netherlands.
The WHO has launched a global survey to assess if the incidence of unexplained hepatitis in children is higher in 2022 compared to the previous 5 years to shed light on whether cases and liver transplants are occurring at higher-than-expected rates. It added that interim results will be shared as soon as they are available.
Jul 12 WHO statement
Routine US childhood vaccines confer profound health, economic benefits
Two studies today in Pediatrics detail the health and economic benefits of routine childhood immunization in the United States. Both studies were led by scientists from RTI Health Solutions and Merck.
One study examined the incidence of 14 vaccine-preventable illnesses with and without universally recommended vaccines for children 10 years and younger over 5 recent years.
Routine immunization lowered the incidence of all studied diseases, from 17% for flu to 100% for diphtheria, Haemophilus influenzae type b (Hib), measles, mumps, polio, and rubella. These decreases correspond to more than 24 million averted cases of vaccine-targeted illnesses for the 2019 US population of 328 million people.
Estimated incidence rates remained highest for flu (13,412 per 100,000 people) and Streptococcus pneumoniae–related ear infections (2,756/100,000).
"Routine childhood immunization in the US continues to yield considerable sustained reductions in incidence across all targeted diseases," the authors wrote.
The other study assessed the economic impact of routine immunization on children born in 2017, finding that vaccines averted more than 17 million illnesses and 31,000 deaths, gaining 853,000 life-years and 892,000 quality-adjusted life-years.
The estimated cost of vaccination ($8.5 billion) was more than fully offset by the $63.6 billion saved by averted disease-related costs. Immunization was tied to $55.1 billion in prevented societal costs, for a benefit-cost ratio (BCR) of 7.5, and $13.7 billion in averted healthcare costs, for a BCR of 2.8.
"In addition to preventing unnecessary morbidity and mortality, routine childhood immunization is cost-saving," the researchers wrote.
In a related commentary, Michael Warren, MD, MPH, and Monique Fountain Hanna, MD, MPH, MBA, both of the US Department of Health and Human Services, said that pediatricians have a key role in combatting vaccine misinformation and promoting immunization in underserved communities.
"A concerted effort across all parts of the health care and public health systems can assure that vaccines remain one of the greatest public health achievements of our time," they wrote.
Jul 13 Pediatrics health-impact study, economic-impact study, and commentary
CDC urges clinicians to be on alert for parechovirus in babies
The Centers for Disease Control and Prevention (CDC) yesterday sent a Health Alert Network (HAN) advisory to health providers warning that parechovirus (PeV), a childhood pathogen with infections ranging from asymptomatic to severe, is circulating in the United States. Since May, multiple states have reported PeV infections in newborns and young infants.
The advisory said all positive specimens tested at the CDC are type PeV-A3, which is most often associated with severe disease.
The CDC urged clinicians to consider PeV in babies presenting with fever, sepsis-like syndrome, or neurologic symptoms like seizure or meningitis without a known cause and test for the virus if signs and symptoms suggest PeV.
Because the United States doesn't systematically track PeV, it's not clear how the number of cases this year compared with previous seasons. PeV testing has become more widely available, and it's possible that increased testing has led to more reported cases.
Jul 12 CDC HAN notice