Flu is here early. Plus Covid, mosquitoes, and more.

Here come the pathogens: flu is coming in hot and early, Covid-19 is peaking, and mosquito-borne diseases are having a bad year in the Southwest.

病原体来了：流感来得又热又早，Covid-19 正在达到顶峰，而蚊媒疾病在西南部的情况又不好。

And with the wave of diseases, come more falsehoods and rumors.

I answer a reader question: Do the benefits still outweigh the risks of the Covid-19 vaccine?

Here’s what’s going on in the world of health and, most importantly, what it means for you.

While levels are still low nationally, flu metrics are ticking up, including emergency department visits.

This is especially true in the West.

在西方尤其如此。

It is early (see graph below).

现在还早（见下图）。

Typically, we see metrics start to increase in October or November.

Flu activity usually starts in the Southeast (Florida and Texas) and then slowly spreads across the country.

流感活动通常始于东南部（佛罗里达州和德克萨斯州），然后慢慢蔓延到全国。

It doesn’t usually start in the West.

它通常不是从西方开始的。

The U.S. doesn’t seem to be alone.

美国似乎并不孤单。

Flu is also increasing early in the U.K., Japan , and other Northern Hemisphere countries.

We don’t know why it’s coming early.

我们不知道为什么它来得这么早。

The Southern Hemisphere’s viral season occurs a few months before the Northern Hemisphere’s, since their winter is our summer, and vice versa.

南半球的病毒季节比北半球的病毒季节早几个月，因为南半球的冬天就是我们的夏天，反之亦然。

This flips the weather and how and when viruses thrive, allowing epidemiologists to look south for clues about what to expect for flu in the north.

这改变了天气以及病毒繁殖的方式和时间，使流行病学家能够向南方寻找线索，了解北方流感的情况。

The flu starting line was a mixed bag.

流感的起跑线是好坏参半。

Argentina’s season started about three weeks early.

阿根廷的产季提前了大约三周。

Chile and South Africa were on schedule, while Australia , New Zealand, and Fiji were unusually quiet through their usual window, then surged unexpectedly in August through September.

智利和南非如期而至，而澳大利亚、新西兰和斐济则在通常的窗口期异常平静，然后在 8 月至 9 月期间意外飙升。

The flu’s later arrival to the Pacific region may be related to the new strain (subclade K) that circulated last year, which really skewed some patterns.

流感较晚抵达太平洋地区可能与去年流行的新毒株（K亚支）有关，这确实扭曲了一些模式。

In Australia, for example, 2025 was their worst flu season on record, and it ended late, peaking just before Christmas.

So flu immunity waned late, causing a later season this year.

Flu season was severe in many places this summer.

In parts of South America, the flu hit hard.

在南美洲部分地区，流感肆虐。

Argentina recorded its highest number of flu-like illness cases in a decade, partly due to its early start, with flu test positivity among outpatients peaking above 45% in late May.

阿根廷录得十年来最高的流感样疾病病例数，部分原因是疫情爆发较早，5 月底，门诊患者流感检测阳性率达到 45% 以上的峰值。

So, the flu is having a weird year across much of the globe.

因此，流感在全球大部分地区度过了奇怪的一年。

Will it mean that we will have a bad season?

这是否意味着我们会经历一个糟糕的赛季？

Not necessarily.

未必。

But epidemiologists will be keeping a close eye on it.

但流行病学家将密切关注这一情况。

What this means for you: Now is the time to get your flu vaccine.

Usually, advice is in October (the common saying is “flu before boo”), but for maximum protection, I think that advice will be late this year.

通常，建议是在十月（俗话说“流感先于嘘”），但为了最大程度的保护，我认为今年的建议会较晚。

Schedule your flu vaccine appointment this week.

本周安排您的流感疫苗预约。

I am.

我是。

Wastewater—a strong indicator of how many people are spreading Covid-19—has clearly peaked at the national level.

A few states in the Midwest are still increasing, but they will soon begin to decrease as well.

If this pattern continues, this summer’s peak will be as high as winter’s, but not as high as last summer’s.

如果这种模式持续下去，今年夏天的峰值将与冬天一样高，但不会像去年夏天那么高。

With reduced spread and increased immunity, we continue to see deaths plummet, falling about 54% each year.

随着传播的减少和免疫力的增强，我们继续看到死亡人数大幅下降，每年下降约 54%。

(See figure below.) This year, if the trend continues, Covid-19 will have contributed to ~9,100 deaths, which is less than half of the deaths caused by the flu each year.

（见下图。）如果这一趋势持续下去，今年 Covid-19 将导致约 9,100 人死亡，不到每年流感造成的死亡人数的一半。

What this means for you: The population-level impact of Covid-19 continues to decline this season and overall, which is fantastic news.

However, the vaccine is still important, especially for high-risk folks .

After some bumps in the road (covered in YLE last week ), the vaccine should now be widely available.

经过一些坎坷（上周 YLE 报道），疫苗现在应该可以广泛使用。

Nationally, this year has been quieter than last year for mosquito-borne diseases, even though the West Nile season started earlier than any year since 2004.

在全国范围内，尽管西尼罗河季节比2004年以来任何一年开始得早，但今年蚊媒疾病的发病率比去年要低。

The one exception is for those of us in the Southwest: Phoenix and California are well above last year.

(Matt over at YLE California has been keeping close tabs on this.)

Thankfully, mosquito activity peaks in August, so it’s now trending downward.

值得庆幸的是，蚊子活动在八月达到高峰，因此现在呈下降趋势。

But those boogers are definitely still out there until they go dormant or die off because of weather changes.

但这些鼻屎肯定仍然存在，直到它们因天气变化而休眠或死亡。

West Nile disease is local by nature: heat, standing water, and how many animals (i.e., hosts) are already immune determine where it flares up.

(Hotspots were in Colorado and Illinois last year.)

What this means for you: The end of the mosquito season isn’t here yet, but it’s close.

这对您意味着什么：蚊子季节尚未结束，但已经接近了。

Expect activity until the first sustained cold snap.

预计活动会持续到第一次持续寒流来临之前。

Until then, use repellent at dusk and dump standing water weekly.

在此之前，请在黄昏时使用驱虫剂，并每周倒掉积水。

With the flu season comes an increase in falsehoods and rumors on social media, and in our daily conversations with family and friends.

随着流感季节的到来，社交媒体上以及我们与家人和朋友的日常对话中的谎言和谣言也随之增加。

Here are some of the top ones in case you find yourself in a conversation with someone in line at the grocery store (like I did just recently):

A lot of people believe this from personal experience, but it’s biologically impossible: the shot doesn’t contain live virus.

很多人从个人经验中相信这一点，但这在生物学上是不可能的：疫苗中不含活病毒。

(The nasal spray uses a weakened live virus that can't cause flu illness, though it may cause a mild runny nose.)

（鼻喷雾剂使用弱化的活病毒，不会引起流感疾病，但可能会引起轻微的流鼻涕。）

Side effects aren’t the explanation either.

副作用也不能解释。

In randomized controlled studies , the only differences between people who received the flu shot and those who received a placebo were increased arm soreness and redness at the injection site.

在随机对照研究中，接受流感疫苗的人和接受安慰剂的人之间的唯一区别是注射部位的手臂酸痛和发红程度增加。

The more likely reason is bad luck: getting exposed to the flu after vaccination but before the shot kicks in, which takes about two weeks.

更可能的原因是运气不好：在接种疫苗后、注射疫苗之前（大约需要两周时间）接触到流感。

Humans have certainly normalized the flu, but it’s a big deal.

About 8% of the U.S. population (anywhere from 3% to 11%, depending on the season) can expect to get the flu each year.

每年大约有 8% 的美国人（根据季节从 3% 到 11% 不等）可能会感染流感。

Since 2010, that has meant between 120,000 and 710,000 hospitalizations and 6,300 to 52,000 deaths every year.

They aren’t perfect, but they do help.

它们并不完美，但确实有帮助。

They don’t always prevent infection, but they are especially good at preventing severe illness and hospitalization.

它们并不总能预防感染，但特别擅长预防严重疾病和住院治疗。

The effectiveness is generally around 40 to 60% when the vaccine is well matched.

疫苗匹配良好时，有效率一般在40%~60%左右。

In the 2019–2020 season, for example, flu vaccines prevented an estimated 7.5 million illnesses, 3.7 million medical visits, 105,000 hospitalizations, and 6,300 deaths.

例如，在 2019-2020 年季节，流感疫苗估计预防了 750 万人次疾病、370 万人次就诊、105,000 人住院治疗和 6,300 人死亡。

Among children, a 2017 study found that flu vaccination halved a child’s risk of death.

Unfortunately, you should get a flu vaccine every year.

Because flu viruses change fast, the flu vaccine is updated annually to target the strains research predicts will be most common this season.

由于流感病毒变化很快，流感疫苗每年都会更新，以针对研究预测本季节最常见的菌株。

Vaccine and/or natural immunity also wanes over time, so you need to get a vaccine annually for optimal protection.

疫苗和/或自然免疫力也会随着时间的推移而减弱，因此您需要每年接种疫苗以获得最佳保护。

“I recently sat in on a doctor visit with a friend who is being treated for cancer.

“我最近去看了一位正在接受癌症治疗的朋友的医生。

When the subject of vaccines came up, her cancer doctor told her to get her flu shot in October and said that he didn’t recommend the Covid-19 vaccine.

当谈到疫苗的话题时，她的癌症医生告诉她要在 10 月份注射流感疫苗，并表示他不推荐接种 Covid-19 疫苗。

I was surprised to hear that.

听到这个消息我很惊讶。

Are blood clots, heart inflammation, long Covid, and other complications still an issue?”

Obviously, I am not part of her clinical care team, and many factors could influence this decision.

显然，我不是她的临床护理团队的成员，许多因素可能会影响这一决定。

But, broadly speaking, this is how I would think about it:

If she received a stem cell transplant or CAR T-cell therapy, this is the right call.

It is advised to delay vaccination for at least 3 months.

During that time, her immune system is heavily suppressed, so the vaccine is less likely to work well.

If she wasn’t getting this treatment, I am disappointed that he didn’t recommend the Covid-19 vaccine for her.

如果她没有接受这种治疗，我很失望他没有为她推荐 Covid-19 疫苗。

People receiving cancer treatments that weaken the immune system have a high risk of severe disease from Covid-19.

接受削弱免疫系统的癌症治疗的人患 Covid-19 严重疾病的风险很高。

This comes down to a very simple question: do the benefits outweigh the risks?

这归结为一个非常简单的问题：好处是否大于风险？

I went searching for numbers, given that we haven’t had a CDC ACIP meeting in a long time.

These are estimates, but they still make clear that the benefits continue to outweigh the risks, especially for those over 65 years old.

这些只是估计，但它们仍然清楚地表明好处仍然大于风险，特别是对于 65 岁以上的人来说。

Benefits: The number of hospitalizations prevented among those over 65 years old is about 1,200 per 1 million doses.

For people 65 and older, the updated vaccine also lowers the risk of Covid-related blood clots, including strokes, heart attacks, and blood clots in the legs or lungs.

对于 65 岁及以上的人来说，更新后的疫苗还降低了与新冠病毒相关的血栓风险，包括中风、心脏病以及腿部或肺部血栓。

Risks : A myocarditis complication isn’t a thing anymore with the Covid-19 vaccine.

This is due to increased immunity (from infections and spaced-out vaccines).

Allergic reactions and Guillain-Barré (maybe) are really the only vaccine-related risks in the data, and they are very, very small.

过敏反应和格林巴利反应（也许）确实是数据中唯一与疫苗相关的风险，而且它们非常非常小。

There is no risk of blood clots from the vaccine.

疫苗不存在血栓风险。

(This was associated with the J&J vaccine early in the pandemic, which is no longer available.)

Flu is here, while Covid-19 and mosquito-borne diseases are decreasing.

Thankfully, we do have vaccines that are, yes, beneficial; the benefits still greatly outweigh the risks.

Thankfully, we do have vaccines that are, yes, beneficial;好处仍然远远大于风险。

Stay healthy out there!

在外面保持健康！

Your Local Epidemiologist (YLE) comprises a team of experts, ranging from physicians to immunologists to epidemiologists to nutritionists, working together with one goal: to “translate” ever-evolving public health science so that people are well-equipped to make evidence-based decisions.

您的当地流行病学家 (YLE) 由一个专家团队组成，其中包括医生、免疫学家、流行病学家和营养学家，他们共同努力实现一个目标：“转化”不断发展的公共卫生科学，以便人们有能力做出基于证据的决策。

The YLE suite of newsletters reaches over 475,000 people across more than 132 countries.

YLE 新闻通讯套件覆盖超过 132 个国家/地区的 475,000 多人。

This newsletter is free to everyone, thanks to the generous support of fellow YLE community members.

感谢 YLE 社区成员的慷慨支持，本通讯免费向所有人开放。

To support the effort, subscribe or upgrade below:

“I don’t need the flu shot” - my personal theory is that people who say that haven’t had actual influenza any time recently, or possibly ever, so don’t realize how truly awful it is.

“我不需要注射流感疫苗”——我个人的理论是，那些说最近或可能从未患过真正流感的人，并没有意识到流感有多么可怕。

Maybe they don’t realize “stomach flu” isn’t the same thing, idk.

I’ve only had the flu once as an adult, a few years before the Covid pandemic started.

I had recently left a job where the vaccine was offered every year at work, so I wasn’t in the habit of needing to schedule it and I must have forgotten to.

我最近离开了一份每年都会提供疫苗的工作，所以我没有需要安排疫苗接种的习惯，而且我一定忘记了。

I was so sick I went to the doctor because I was certain something must be really wrong.

Flu hadn’t occurred to me because I didn’t really know the symptoms, but sure enough, one nasal swab later I was diagnose with influenza a.

I have never been more fatigued in my life.

我一生中从未如此疲惫过。

I have since had 2 kids and that first trimester fatigue hit me in a similar way.

But, bonus, your body hurts everywhere!

但是，额外的好处是，你的身体到处都痛！

And flu has its own “long” syndrome - I had lingering fatigue for months afterwards.

And I was pretty young (30), healthy, had no kids or even time consuming pets.

I could afford to live on my couch for a week.

我可以在沙发上住一个星期。

I was interested that your discussion of covid related mostly to hospitalizations and deaths, with deaths being the worst outcome.

I didn't see any mention of long covid, which sounds like living hell if it's at all severe.

My 36-year-old child (who's genderfluid) has had it for 4 years since getting covid the 2nd time.

Their symptoms are mostly fatigue and brain fog, with dysautonomia and trouble sleeping.

But we're looking at restricted activity and inability to work indefinitely, perhaps for a lifetime.

但我们正在考虑活动受到限制，并且无法无限期地工作，也许是一生。

I hear up to 10% of those who get covid get long covid.

Putting aside personal suffering, the economic cost is significant.

Shouldn't this be tracked and mentioned alongside the risk of hospitalization and death?

(Note: I think part of the problem here is that people with long covid are very reluctant to go out in public, so they're invisible to policymakers.)

（注：我认为这里的部分问题是长期感染新冠病毒的人非常不愿意去公共场合，所以政策制定者看不到他们。）