【JISA Interpretation】 Should You Stock Up on Oseltamivir as Influenza A Spreads? Cold Teacher Helps You Avoid the Pitfalls 爱博物    2025-09-12

【Preface】
Recently, Influenza A has been spreading from north to south across China. Today, we’ve invited Cold Teacher to share some insights on medication for Influenza A.

I’ve previously shared some information about Influenza A, and recently, many people have been asking me about medications for it, such as whether they should stock up on Oseltamivir at home, how much to stock up on, and when to start taking it.

Today, I’ll provide some answers from a personal perspective, which you can use as a reference.

First, regarding whether to stock up on Oseltamivir, my advice is to assess your family’s situation. If there are vulnerable individuals in your household, such as the elderly or children, who haven’t received the flu vaccine since last fall, then I recommend keeping some on hand.

Especially consider the availability of the medication in your area. For example, where I am, local pharmacies are out of stock. While some platforms may have it, delivery times are often lengthy. Oseltamivir is most effective when taken within 48 hours of symptom onset. If you wait until symptoms appear to purchase it, and it takes 2-3 days to arrive, it will be too late.

Next, let’s talk about the timing of medication. Many people find themselves in a dilemma when flu-like symptoms appear: Should they start taking medication? At this point, it’s unclear whether it’s actually Influenza A.

For such situations, my suggestion is that if you experience flu-like symptoms, such as fever, and have the medication at home, you can start taking it orally. If a hospital test later confirms it’s not Influenza A, you can stop taking the medication.

Compared to the potential side effects of Oseltamivir, the benefits of shortening flu symptoms and reducing risks are worth it. Moreover, Oseltamivir itself is listed as a preventive medication for the flu, so the risks are not as high as many people think.

Here’s another point: Many people go to the hospital for Influenza A and B tests, and even if the results are negative, doctors still prescribe Oseltamivir. This isn’t because doctors are prescribing indiscriminately; rather, a single test may not provide conclusive evidence. Based on their clinical experience, doctors may still suspect the patient has the flu.

A friend of mine recently encountered this situation.

Their child developed a fever on the 8th. After seeking medical attention on the 9th, a flu test came back negative for both Influenza A and B. The child continued to have a fever, so they went back to the hospital on the 10th for another test, which confirmed Influenza A.

This is actually quite common. After three years of the pandemic, everyone should be aware that current testing methods for viruses like this can sometimes yield false negatives or inaccurate results. So, even if your test doesn’t detect Influenza A, it doesn’t rule out the possibility.

But there’s a follow-up issue: If Influenza A is confirmed on the third day of symptoms, which is beyond the recommended 48-hour window for Oseltamivir, is there still value in taking it?

Strictly speaking, taking Oseltamivir on the third day still offers some benefits, though significantly less than within 48 hours. In such cases, it’s best to follow your doctor’s advice.

Finally, here are two easily overlooked pitfalls when purchasing medication.

First, there’s no need to rush only for Oseltamivir. Baloxavir marboxil is also an effective antiviral drug for the flu.

However, regardless of which drug you purchase, pay close attention to the dosage on the packaging.

Let’s start with Oseltamivir. The recommended usage is to take it within 48 hours of symptom onset, twice daily for five days.

Take the most common sachet form of Oseltamivir as an example. Each box contains 10 sachets of 15mg each. Even for the smallest pediatric dose (for children weighing less than 15kg), a full course requires two boxes. Many parents buy only one box, only to find it’s not enough halfway through.

For older children or adults, the discrepancy is even greater. The recommended dosage for children over 40kg is the same as for adults: 75mg per dose, twice daily for five days. This means one box is only enough for one day.

For such cases, I recommend purchasing the 75mg capsule form, ideally in boxes of 10 capsules. Many Oseltamivir capsules now come in boxes of six, which is inconvenient—one box isn’t enough, and two boxes are excessive.

Now, let’s discuss Baloxavir marboxil. This medication requires only a single dose, also based on weight.

However, there’s also a packaging dosage issue. Currently, Baloxavir marboxil is sold in two packaging options: 20mg x 2 per box and 40mg x 1 per box. Both options total 40mg. However, if an adult weighs over 80kg, they need to take two boxes. Many people overlook this and only realize one box isn’t enough when it’s time to take the medication.

That’s all for today. I hope this helps you avoid these pitfalls. Additionally, regarding virus testing, JISA Academy offers cutting-edge research projects on virus detection and species identification. This summer’s projects are currently enrolling. Interested students can click the link below for more information.

For more information, please contact the iBOWU advisor:

Teacher Zhang: 13910908618 (also WeChat ID)
Teacher Zha: 13910312020 (also WeChat ID)

About iBOWU · JISA Academy
JISA Academy™ is China’s first youth science academy initiated by non-governmental forces. Launched by iBOWU, a well-known platform for youth scientific research and academic projects in China, it aims to provide high-quality scientific practice platforms for Chinese youth.

JISA Academy has received investments from BGI Group and TAL Education Group’s industry fund. Leveraging strong scientific and capital backing, JISA Academy has gathered dozens of multidisciplinary frontline scientists and partnered with dozens of university and research laboratory resources across China, the United States, Denmark, Norway, Singapore, Australia, and other countries. It is dedicated to offering high-end STEM advanced academic projects and elite training programs for students, striving to cultivate the scientific spirit of Chinese youth and contribute to the reserve of scientific and technological talent for China and the world.