[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"article-detail":3},{"lang":4,"article":5,"alternate":20,"related":21,"latest":30},"en",{"id":6,"slug":7,"title":8,"content":9,"summary":10,"thumbnail":11,"metaDescription":12,"metaKeywords":13,"created":14,"modified":15,"author":16,"authorEn":16,"categoryId":17,"commentCount":18,"thumbnailToContent":19},12574,"flu-vaccine-immunity","Flu Season Is Back: Why the Annual Flu Shot Is a Biology Lesson Worth Taking","\u003Cp style=\"margin:0 0 18px;\">In the latest weekly respiratory surveillance report (week 38, September 14–20, 2026), influenza had climbed back to the \u003Cstrong>top spot\u003C\u002Fstrong> among pathogens detected in outpatient flu-like illness samples, at a \u003Cstrong>19.0% positivity rate\u003C\u002Fstrong> — ahead of rhinovirus (10.6%) and SARS-CoV-2 (9.3%). Southern provinces were trending upward, while northern activity remained low. Of the flu-positive samples, \u003Cstrong>69.9% were influenza A\u003C\u002Fstrong> — dominated by \u003Cstrong>A(H3N2)\u003C\u002Fstrong> at 94.5% — and \u003Cstrong>30.1% were influenza B (Victoria lineage)\u003C\u002Fstrong>. A national vaccination guidance for the 2026–2027 season has been published.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">For most people, the practical takeaway is simple: \u003Cstrong>get the flu shot\u003C\u002Fstrong>. But the \"why\" is a genuinely interesting piece of biology.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>The Flu Is a Virus, Not a Bacterium\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">Influenza is caused by \u003Cstrong>RNA viruses\u003C\u002Fstrong> of the family Orthomyxoviridae — not by bacteria. This matters for treatment: antibiotics kill bacteria, and they do nothing against the flu. The \"A\" and \"B\" in flu classifications refer to virus types, and the H and N codes (H3N2, H1N1) name two surface proteins: \u003Cstrong>hemagglutinin (H)\u003C\u002Fstrong>, which the virus uses to dock onto host cells, and \u003Cstrong>neuraminidase (N)\u003C\u002Fstrong>, which helps new virus particles escape.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20260927\u002F8bb4764f794c4183867d21cffc207144.png\" alt=\"Influenza virus particle structure with surface spikes and RNA genome\">\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>Why You Need a New Shot Every Year\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">Unlike chickenpox or measles, flu immunity does not last for decades. The reason is \u003Cstrong>antigenic drift\u003C\u002Fstrong>: as the virus replicates, its surface proteins accumulate small mutations, so the \"shape\" your immune system memorized last year no longer matches this year's virus perfectly.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Each season, vaccine manufacturers update the shot to match the strains expected to circulate. Your immune system, meeting the updated vaccine, builds fresh antibodies and \u003Cstrong>memory B and T cells\u003C\u002Fstrong>. When the real virus arrives, those memory cells respond fast enough to blunt the infection — or prevent it entirely. Miss the shot, and your immune system meets an unfamiliar virus from scratch, which is exactly the slow, severe scenario vaccines are built to prevent.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>Who Should Get It First\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">Guidelines prioritize groups at higher risk of severe flu: older adults, young children, people with chronic conditions, pregnant women, and healthcare workers. But healthy adults benefit too — the shot reduces both your own risk and the chance you pass the virus to someone vulnerable.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>The Scale Problem: You Can't See a Virus With a Light Microscope\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">Here is a humbling biology fact: a flu virus is roughly \u003Cstrong>100 times smaller than a typical bacterium\u003C\u002Fstrong> — around 100 nanometers. It is far below the resolution limit of an ordinary light microscope. You need an electron microscope to see one. That is why classroom specimen collections hold bacteria and cells, but never viruses.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Bacteria, by contrast, are full cells you can see clearly under a light microscope. Many respiratory pathogens are bacteria — whooping cough, for example, is caused by \u003Ci>Bordetella pertussis\u003C\u002Fi>, a Gram-stained rod. Flu is a virus and whooping cough is a bacterium: both set up camp in the respiratory tract, but one shrugs off antibiotics while the other responds to them.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20260927\u002Fab32ccc8449e4584a90f45dbba7d2a77.png\" alt=\"Viruses changing shape as immune cells fail to recognize them, antigenic drift illustration\">\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20260927\u002F12e476a6e1f94a749826b10bd6acd2b1.png\" alt=\"Gram-stained bacteria rods under microscope, respiratory bacterium morphology\">\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Want to see what a respiratory bacterium looks like under a microscope? \u003Cstrong>WWAI\u003C\u002Fstrong> is an AI-powered biology encyclopedia that answers your biology questions instantly and lets you observe real microscope slide specimens online — including a \u003Cstrong>Gram-stained Bordetella pertussis specimen\u003C\u002Fstrong> showing the rods that cause whooping cough. Search \"WWAI\" in your app store and download it today.\u003C\u002Fp>\n\u003Cdiv class=\"dp-template-card\" style=\"border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,0.1);margin:10px 0;max-width:100%;overflow:hidden;width:100%;\">\n \u003Ca style=\"display:block;text-decoration:none;\" href=\"https:\u002F\u002Fyun-hub.chat\u002Flink\u002F?app=wwai&clickid=stellarx&dplink=specimenid%3D1189\" target=\"_blank\">\u003Cimg class=\"image_resized\" style=\"display:block;height:auto;max-width:100%;width:100%;\" src=\"\u002Fattachment\u002F20260824\u002F5ba5dd3c38404fe785f43c44423830de.png\" alt=\"5ba5dd3c38404fe785f43c44423830de\">\n  \u003Cbutton style=\"align-items:center;background-color:#1f983e;border-radius:0 0 25px 25px;border-style:none;color:#ffffff;cursor:pointer;display:flex;font-family:Times New Roman;font-size:19px;height:40px;justify-content:center;padding:0;width:100%;\">EXPLORE NOW\u003C\u002Fbutton>\u003C\u002Fa>\n\u003C\u002Fdiv>\n\u003Cp style=\"color:#8a8a8a;font-size:13px;margin:0 0 10px;\">\u003Ci>References:\u003C\u002Fi>\u003C\u002Fp>\n\u003Cp style=\"color:#8a8a8a;font-size:13px;margin:0 0 6px;\">\u003Ci>[1] All illustrations are AI-generated.\u003C\u002Fi>\u003C\u002Fp>\n\u003Cp style=\"color:#8a8a8a;font-size:13px;margin:0 0 6px;\">\u003Ci>[2] Surveillance and vaccination-guidance data adapted from a public health report for the 2026–2027 flu season, 2026-09-26.\u003C\u002Fi>\u003C\u002Fp>","","\u002Fattachment\u002F20260927\u002Fa31b409e60e04e7dafe25f720e607e26.png","Flu positivity is climbing again in the fall surveillance data, with H3N2 dominating. Here's the biology behind the annual flu shot: antigenic drift, antibody memory, and why influenza is a virus, not a bacterium.","stellarx, wwai, flu season, flu shot, influenza vaccine, bordetella pertussis cells","2026-09-27 01:13:00","2026-09-27 01:26:56","Science Guide Wwai",77,0,true,null,{"prev":22,"next":26},{"id":23,"slug":24,"title":25,"categoryId":17},12575,"textbook-diet-nutrition","The \"Textbook Diet\": 7 Nutrition Rules Most Diet Advice Misses",{"id":27,"slug":28,"title":29,"categoryId":17},12573,"matcha-nutrition-science","Matcha Benefits: What 3 Grams of Matcha Powder Actually Contains",[31,36,41,46],{"id":32,"slug":33,"title":34,"thumbnail":35,"categoryId":17},12685,"food-adulteration-history-bwxa","Ancient Food Was Never Pure: Urine, Lye, and Fake Fish","\u002Fattachment\u002F20261001\u002F03bbfa285e6545d6b3144a2fb3e790f9.webp",{"id":37,"slug":38,"title":39,"thumbnail":40,"categoryId":17},12684,"glowing-algae-story-zptc","When Lockdown Laziness Grew Glowing Algae","\u002Fattachment\u002F20261001\u002F2915a99ca6dd44bb99d4131bc2f639b5.webp",{"id":42,"slug":43,"title":44,"thumbnail":45,"categoryId":17},12683,"alpha-gal-syndrome-gmht","Why a Tick Bite Can Make You Allergic to Red Meat","\u002Fattachment\u002F20261001\u002Faa24a6f7e36b4b2fb5b8a0f6c3bfd1d8.webp",{"id":47,"slug":48,"title":49,"thumbnail":50,"categoryId":17},12682,"centipede-leg-count-comparison-lqzv","Who Has More Legs: House Centipede or Centipede?","\u002Fattachment\u002F20261001\u002Fb139d5c1b20648f39e4eca5fb29ac3f2.webp"]