As the autumn’s cool weather settles in, so does flu season – bringing with it the familiar experiences of sniffles, fever and cough.

Every year, influenza – the flu – affects millions of people. Most will experience the infection as a mild to moderate illness – but for some, it can be severe, potentially resulting in hospitalization and even death.

While the start of flu season may feel routine, it’s important to remember that the virus changes every year, making annual vaccination an important part of staying healthy.

What to expect this flu season

Public health experts are closely watching how this year’s flu season unfolds. Early reports suggest that the U.S. may see a moderate level of flu cases, partly because last year’s flu activity was high and it’s uncommon to have two severe flu seasons in a row.

However, the U.S. also uses data from the Southern Hemisphere’s earlier flu season, which lasts from April to October, to help predict what the season might look like. There, the flu season has been more severe than in years past.

Taken together, that means there could be a significant number of flu cases in the U.S., particularly among children, older adults and those with chronic health conditions.

Each year, the flu vaccine is updated to best match the strains of influenza expected to circulate. Because flu viruses mutate frequently, the effectiveness of the flu vaccine can vary each year. However, even when the match between the seasonal flu and the vaccine that is designed around it isn’t perfect, vaccination remains the best protection against severe illness.

In the U.S., all flu vaccines for the 2025-2026 season will be trivalent – which means they are formulated to protect against the three main groups of influenza virus strains. These are an A (H1N1) virus, an A (H3N2) virus and a B/Victoria virus.

Vaccine availability

Recent vaccine policy changes have created some confusion, particularly around COVID-19 vaccines. Many people are wondering if getting the flu vaccine has become more complicated. The good news is that flu vaccines remain widely available and accessible. Pharmacies, doctors’ offices, public health clinics and many workplaces are offering the seasonal shot, often at little or no cost.

The 2025-2026 flu vaccine is available now. Manufacturers start shipping vaccines doses in July and August to ensure access by September. While public health experts won’t know the exact effectiveness of the flu vaccine until flu season is over, the flu shot usually cuts your chances of needing to see a doctor for the flu by about half.

Vaccination helps reduce the severity of illness, the likelihood of hospitalization and the spread of infection within our communities.

It’s important to note that you can get the flu shot at the same time as other vaccines, such as the COVID-19 vaccine or the RSV and pneumonia vaccines for older adults, without compromising effectiveness. If you’re unsure which vaccines are right for you, your health care provider or pharmacist can help you decide based on your age and health status.

Who should get the flu shot

The Centers for Disease Control and Prevention recommends that everyone 6 months and older receive the flu vaccine each year, with rare exceptions. That aligns with guidelines from other organizations, such as the American Association of Pediatrics.

The flu vaccine is especially important for:

• Adults 65 and older

• Children under 5 – and particularly those under 2

• Pregnant people

• People with chronic conditions such as asthma, diabetes or heart disease

• Health care workers and caregivers

Even if you’re healthy and rarely get sick, getting vaccinated protects not only you but also those around you who may be more vulnerable.

Practical prevention tips

In addition to vaccination, everyday actions help reduce the spread of flu and other respiratory viruses:

• Wash your hands frequently with soap and water.

• Cover your coughs and sneezes.

• Stay home if you’re feeling unwell.

• Consider wearing a mask in crowded indoor spaces during peak flu activity, particularly if you have a cough.

Even though flu season is part of life, serious illness doesn’t have to be. By staying informed, getting vaccinated and practicing healthy habits, everyone can play a role in keeping their communities safe and healthy.

If you haven’t gotten your flu shot yet, now’s the time to protect yourself, and those you care for, this flu season.

Libby Richards, Professor of Nursing, Purdue University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to This email address is being protected from spambots. You need JavaScript enabled to view it..

What is meant by solar storm and solar wind? – Nihal, age 11, Amalapuram, India

Every day on Earth, you experience weather. You feel the wind blowing and see clouds move across the sky. Sometimes there are storms where the wind gets really strong, it might rain, or there might be thunder and lightning.

Did you know that there’s weather in space too? It all starts with the Sun.

The Sun: The bright star in our solar system

The Sun is a very hot, very big ball of gas at the center of our solar system. Its surface can reach a blistering 10,800 degrees Fahrenheit (6,000 degrees Celsius). That’s nearly five times hotter than lava that spews from volcanoes on Earth, and just like lava, the Sun glows from the heat.

The Sun is made up of what solar physicists like us call plasma.

Normal gases, like the air you breathe on Earth, are made up of atoms bouncing around. Atoms consist of a positively charged bundle of particles called the nucleus and negatively charged particles called electrons. The nucleus and the electrons are tightly stuck together so that atoms are overall neutral – that is, they have no charge.

A gas becomes a plasma when the atoms it’s made of become so hot that their negatively charged electrons split apart from their positively charged nuclei. Now that the charged particles are separated from each other, the plasma can conduct electricity, and magnetic fields may pull the plasma or push it away.

Solar wind blows out of the Sun all the time

Sometimes, the Moon lines up with Sun, blocking it from view and turning the sky dark. This phenomenon is called a total solar eclipse. During an eclipse, you can see faint, wispy structures surrounding the Moon that extend across the sky. In that moment, what you are seeing is the Sun’s atmosphere: the corona.

The corona can reach millions of degrees, which is much hotter than the Sun’s surface. In fact, the corona is so hot that the particles shoot out of the Sun, escaping from the Sun’s gravity, engulfing the entire solar system. This stream of plasma is called the solar wind.

The solar wind’s invisible, continuous gust of plasma fills a bubble in space that extends far beyond the orbit of Pluto. It can reach up to 2 million miles per hour (3 million kilometers per hour) – at that speed, the solar wind would take less than a minute to circle the Earth. For comparison, the International Space Station takes 90 minutes to go around the Earth.

While it’s hard to see the solar wind directly in photos once it leaves the corona, we can measure the gas directly with instruments in space. Scientists have recently gotten up close and personal with it by sending missions such as the Parker Solar Probe closer to the Sun than ever before. The Parker Solar Probe flies directly into the solar wind and measures the gas directly just as it escapes the Sun – like a weather station.

The Parker Solar Probe also has a specialized camera that points sideways to see the Sun’s light as it scatters off the solar wind. Light scattering is the same process that makes the sky blue on Earth.

Big solar explosions

The solar wind surrounds and engulfs the Earth and other planets all the time, but most of the time it is safely guided around us by our planet’s magnetic field. However, occasionally the Sun also generates huge explosions that release big clouds of plasma into our solar system, some of which are directed toward Earth. These massive events are called coronal mass ejections.

Compared to the solar wind, which is always blowing, coronal mass ejections are short-lived but extreme. You can think of them as solar storms. Solar storms also involve one important force that doesn’t really play a role in the weather on Earth: magnetism.

The Sun is like a giant magnet. All magnets create what we call magnetic field lines, which are lines along which charged particles such as plasma have an easy time traveling. The Sun’s magnetic field lines can be very twisted, and the solar wind and coronal mass ejections deform and drag them outward from the Sun.

When these solar storms reach Earth, their coiled magnetic fields can sometimes interact with our planet’s own magnetic field and cause disturbances called space weather.

Space weather is caused by the Sun

The Earth has a magnetic field and a protective bubble: the magnetosphere. The magnetosphere shields us from the Sun’s solar wind and solar storms, acting like a force field to keep living things safe from the energetic particles released by the Sun.

Most of the time this protective bubble works so well that you can’t tell that there is anything special happening out in space. During particularly big storms, however, some solar wind plasma can make it down into the Earth’s atmosphere. As coronal mass ejections pass over Earth, their magnetic field can interact with Earth’s magnetic field. The Sun and Earth’s magnetic field lines untangle and rearrange, and for a short while these fields can link together and let the Sun’s plasma in.

When this happens, it can cause big magnetic storms all over the world. This interaction between ejections from the Sun and the Earth is what scientists refer to as space weather.

Space weather is just like the weather on Earth, generated by its atmosphere. It is important for scientists to understand and predict this space weather, as it can lead to power blackouts, interrupt communication and even cause satellites to prematurely fall down to Earth.

Besides these dangers though, space weather can create beautiful light shows in the sky called Northern Lights, or aurora borealis, and Southern Lights, or aurora australis. You can observe these if you’re near the North or South Poles. If you ever get a chance to see them, remember what you’re seeing is space weather, the result of eruptions and solar wind from the Sun.

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Yeimy J. Rivera, Researcher in Astrophysics, Smithsonian Institution; Rosa Tatiana Niembro Hernández, Astrophysicist, Smithsonian Astrophysical Observatory, Smithsonian Institution, and Samuel Badman, Researcher in Astrophysics, Smithsonian Institution

This article is republished from The Conversation under a Creative Commons license. Read the original article.