“Weird”? COVID-Influenza Season Combo Increases Vaccination Needs

(Conversation) — As winter approaches throughout the United States, as a hospital Can continue to drag In severe cases of COVID-19, the flu season poses a particularly ominous threat this year.

We have vaccination policy Mathematical modeling Of infectious diseases. Our group, Institute of Public Health Dynamics The University of Pittsburgh has been modeling influenza for over a decade. one of us I am a member of the Centers for Disease Control and Prevention Advisory Committee on Immunization Implementation And CDC Influenza vaccine efficacy network..

Our recent modeling work was last year Truncate the flu season Influenza cases may surge this season.

Anti-COVID-19 strategy also reduced influenza

The United States has undergone dramatic changes as a result of numerous measures taken in 2020 to control COVID-19 infections, including travel restrictions, masking, social distance, school closures, and other strategies. I’ve done it. Influenza reduction Other infectious diseases during the last season of influenza.

Influenza-related deaths in children start at nearly 200 in the 2019-2020 season one The season from 2020 to 2021. Overall, during the 2020-2021 flu season, Minimum number of cases recorded In recent American history.

Relieving the flu is good, but it can mean that the flu will be hit harder than usual this winter. This is because much of the innate immunity that people develop against a disease is due to the spread of the disease throughout the population. Many other respiratory viruses showed similar declines during the pandemic, and some of them Contains seasonal respiratory syncytial virus, or RSV, Have got Dramatically increased Schools have reopened and social distance, masking and other measures have decreased.

Decoding virus infection

Multiple factors are involved in immunity to influenza. Influenza is caused by several strains of mutated RNA virus At various rates each year Occurs in SARS-CoV-2, A virus that causes COVID-19.

The level of a person’s existing immunity to this year’s influenza strain depends on several variables. They include how similar the current strains are to the strains the child was originally exposed to, whether the circulating strains are similar to the strains previously experienced, and if they occur, their influenza infection. Includes how recent it was.

And, of course, human interactions such as children gathering in the classroom, attending large gatherings, and the use of protective measures such as wearing masks all cause the virus to spread among people. It will affect you somehow.

There are also variables due to vaccination.Herd immunity by vaccination is based on the percentage of people who receive influenza vaccine in a specific season and the vaccine. Circulating influenza strain..

There is no precedent for’twindemic’

Given the limited spread of influenza in the US population last year, our research suggests that the United States may see an influenza pandemic this season.Pair with existing threats in Highly infectious delta variant, This can cause a dangerous combination of infections, or a “cold”.

COVID-19 model And other infectious diseases are at the forefront of predicting COVID-19 pandemics and are often proven to predict cases, hospitalizations, and deaths.

However, there is no historical example of this kind of double and simultaneous epidemic. As a result, traditional epidemiological and statistical methods are not very good at predicting what is likely to happen this season. Therefore, a model that incorporates a mechanism of how the virus spreads can make better predictions.

Two separate methods were used to predict the potential impact of last year’s decline in influenza cases during the current 2021-2022 influenza season.

In our recent study It has not been peer reviewed yet, Applied Modeling system It simulates real-world population interactions at home, at work, at school, and in neighborhoods. This model predicts that the United States could see a big spike in this season’s flu cases.

of Another preliminary survey, We used traditional infectious disease modeling tools to divide the population into susceptible people, infected people, recovered people, hospitalized or dead people. Based on our mathematical model, we predict that the United States may have more than hundreds of thousands of additional hospitalizations of 102,000. Usually occurs during the flu season.. These numbers assume no change from the usual influenza vaccine intake and efficacy that lasts from this fall to the flu season.

Personal behavior and vaccination issues

NS Typical flu season It usually causes 30-40 million symptomatic illnesses, 400,000-800,000 hospitalizations and 20,000-50,000 deaths.

This outlook is Ongoing battle with COVID-19Increases the chances of twins overwhelming the medical system as a hospital or ICU Some parts of the country overflow Severe COVID-19 patients.

Our study also emphasizes how infants may be particularly at risk because they were less exposed to influenza in the previous season and therefore have not yet developed broader immunity compared to adults. Did. In addition to the burden on children, childhood influenza is an important driver of influenza in the elderly, as children are infected with the flu. Grandparents and other elderly people..

However, there are optimistic reasons because people’s behavior can significantly change these outcomes.

for example, Simulation research Incorporating people of all ages and finding that increasing vaccination among children could reduce children’s infections by half. And this year, it turns out that if only 25% more people are vaccinated against the flu than usual, it is enough to reduce the infection rate to normal seasonal flu levels.

There is a great deal of variability in immunization rates, adherence to social distance recommendations, and wearing masks throughout the United States.Therefore, the flu season, as we have seen, can experience significant fluctuations from state to state. COVID-19 infection pattern..

All this data suggests that flu shots are important each year, but this year is most important to prevent a dramatic increase in flu cases and prevent overwhelming U.S. hospitals. increase.

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