The flu stalking us in Australia right now should scare you, almost to death.

Update: February 16, 2018.

“The flu vaccine is more effective than expected, federal health officials said on Thursday at a special news conference held to discuss the dangerous flu season, which is expected to kill more than 50,000 Americans.

This year’s vaccine is about 25 percent effective against the H3N2 strain of flu that is causing most illnesses and deaths, said Dr. Anne Schuchat, acting director of the Centers for Disease Control and Prevention.

In a bigger surprise, the vaccine is about 51 percent effective in children, according to the C.D.C.’s preliminary analysis.

In Australia, the same vaccine was rated about 10 percent effective overall against H3N2, and a recent Canadian analysis found it to be about 17 percent effective there. (The C.D.C.’s final analysis will not be ready until the flu season ends in late spring.)

Dr. Schuchat and Alex M. Azar II, the new secretary of health and human services who led the news conference, also pointed to a C.D.C. study published Monday in the journal Pediatrics showing that two-thirds of the 675 children and teenagers who died of flu between 2010 and 2016 had not gotten the vaccine the year they died.”

Update: February 10, 2018.

The current quadrivalent flu vaccines contain antigens for 4 flu viruses — two types of influenza A, H1N1 and H3N2, and two types of influenza B, B/Phuket/3073/2013 — like virus (Yamagata lineage) and B/Brisbane/60/2008 — like virus (Victoria lineage).

The vaccine is highly effective against all but influenza A H3N2 virus. It is very important to be protected against all circulating flu viruses. The CDC estimated that the vaccine is over 70% effective against the two influenza B viruses, and over 60% effective against the H1N1 variant.

The vaccine has unknown effectiveness against the H3N2 virus, but according to an analysis by the Australian government, the effectiveness may be as high as the upper 30% range.

Using early data the CDC estimates the current flu vaccine’s effectiveness against the H3N2 strain could be around 30%.

The effectiveness estimates for 2017–2018 are 43 percent against the predominant influenza A (H3N2) viruses and 73 percent against influenza B viruses.

Every year the flu virus does an annual migration across the world, hitting the Southern Hemisphere during its winter, the Northern Hemisphere right about now, and hanging out in the tropics in between — especially in parts of Asia. That means we look to Australia to know what is coming to us... and Australia is seeing one of its worst flu years on record, with over 2½ times more infections than in the same period last year. Influenza A (H3N2) is the predominant circulating influenza A virus this year, and 81% of the confirmed flu deaths have been due to this strain.

U.S. Flu Vaccine Effectiveness Network data for the 2016–2017 influenza season showed this year’s flu vaccine is 48 percent effective in preventing laboratory-confirmed influenza A and B viral infection associated with medically attended acute respiratory illness.

The exact effectiveness estimates are 43 percent against the predominant influenza A (H3N2) viruses and 73 percent against influenza B viruses.

When older people die from flu, it is usually due to complications like pneumonia. But young healthy people get to die of the flu in special ways. Influenza A just loves young, healthy people, taking them down within days of exposure. In fact, it is more deadly to healthy young adults than to the elderly and infants.

One of the most striking complications when young people get influenza A subtypes is blood hemorrhaging from mucous membranes, especially from the nose, stomach, and intestine, but also of the eyes, ears, from the skin in general. Each one of those organs is lined with beautiful epithelial cells that the virus colonizes. The body swiftly attacks the tissue, trying to kill the cells that are producing new viral particles. Imagine your child’s face turning into a fountain of blood.

Another horrific complication is brain swelling, or encephalitis. This brain swelling develops mainly in children below 5 years of age, either on the day that influenza signs appeared or the day after. There is no time to do anything, and practically no warning. Technically, the virus replicates in the nasopharyngeal epithelium and disrupts the olfactory mucosa. The “stimuli” is transmitted to the brain via the olfactory nerve system, eventually activating the glial cells (support cells of the neurons in the brain), which induces the production of pro-inflammatory cytokines. The resulting cytokine storm results in neural cell damage as well as apoptosis of glial cells (due to TNF-induced mitochondrial respiratory failure for my fellow science nerds if you made it this far). The disruption of the blood-brain barrier progresses rapidly, resulting in death.

In other cases of flu, fluid accumulates in the lungs, making it difficult to breathe and preventing oxygen from reaching the blood stream. Scientists have found a protein in the flu virus called M2, which in turn damages a protein responsible for clearing fluid from the lungs by increasing the amount of oxidants, or free radicals, within the cells. Complicating matters is that robust, healthy, young immune systems don’t tend to use bullets when fighting an invader like flu, they use atomic bombs. The young healthy immune system often mounts an extreme response to the foreign invader that ends up causing more tissue damage than the pathogen does. When the response is too strong, and healthy cells are killed along with infected cells, the collateral damage can be devastating to the lungs’ delicate tissues. Either way, you drown in your own lungs as the liquified tissue no longer supports gas exchange.

Flu is particularly dangerous for pregnant women. The flu virus can penetrate the placental barrier and infect the developing fetus. Not only does spiking a high fever during pregnancy correlate with risk of autism and schizophrenia, but is causative for miscarriage, preterm labor and premature birth and birth defects. Women can and SHOULD receive the flu shot at any point during their pregnancies, regardless of trimester, as soon as it becomes available in their area.

A pregnant woman’s heart and lungs are already doing extra work during pregnancy. The flu shot has been given to millions of pregnant women over many years. Flu shots have never been shown to cause harm to pregnant women or their babies, but pregnant women have been shown to be at increased risk for morbidity and death from flu. In my previous post, Is the Flu Shot Safe During Pregnancy?, I detailed the many research studies that show the flu vaccine is safe and effective for pregnant women.

The risk of stillbirth is 51 percent less likely among vaccinated mothers, as opposed to unvaccinated mothers, with the largest reduction in stillbirths coming just after flu season ends. Vaccination of expectant mothers against flu has been recommended as far back as 1960 in the US.

Every year I get the same questions about the flu shot. I have compiled my answers along with some general information on how the vaccine works. I hope this helps you to decide that the flu vaccine is right for you and your family.

Question: How do viruses and vaccines work anyway?

Answer: Viruses hijack our cells because they cannot replicate on their own. Viruses are basically a ribonucleic acid syringe. They are paragons of Darwinian evolution, having shed every single functional organelle (for example, they do not have mitochondria, ribosomes, Golgi apparatus, endoplasmic reticulum, or nuclei). They inject their DNA or RNA right into our own cells where it gets incorporated into our own DNA, where it is then translated and transcribed, so that our cell’s protein production machines are put to work, making new viral particles. The immune system protects the body from viruses. Specialized cells (Macrophage and T cells) roam around and when they encounter a viral particle they capture it, engulf it, break it apart, and present a small piece of it to the immune system. The immune system then goes to war, and becomes an antibody factory, making antibody-soldier cells against the small piece of virus that has been shown to it. Virtually hundreds of antibodies are released all day everyday by our immune systems. Vaccines work by mimicking a virus and stimulating the immune system to build up defensive antibodies against the pathogen if it is ever encountered again. You want your immune system to detect the most deadliest and destructive viruses before they can insert their DNA (or RNA) into yours.

You get symptoms after a viral infection because your body tries to kill the cells (YOUR CELLS) that are infected. Symptoms come from instructions provided to your cells by the virus itself, for example, it will make you cough and sneeze (etc). The virus uses your body to spread itself to other people. It doesn’t have legs or arms or independent locomotion, it needs you to spread it around.

Structure of an influenza particle

Question: Can’t I STILL get the flu, even if I get a flu shot?

Answer: Yes. The flu shot is only as good as your own immune system’s response to it!!! The effectiveness does not come from the vaccine, it comes from you. If your body creates a strong response to the vaccine then your immunity to flu will be high. If you have a weak response then your immunity will be low, and you may still get the flu. That is why the effectiveness of the vaccine can vary between people. Usually, the flu vaccine is “quadrivalent”, meaning you will be vaccinated against only the 4 most deadly strains of flu. That being said, the shot does ALSO give you protection in general from the flu (not just to strains in the vaccine). Getting the shot “primes” your body to recognize and fight all strains of the flu. So, if you are infected with a strain not covered by the vaccine your symptoms will be less severe, and even the most severe consequences of infection, like death, can be prevented.

Question: Why bother getting the shot then, if I can still get the flu?

Answer: Even just a ‘simple’ hospitalization from the flu will cost on average up to $4,000, and that number doesn’t include your lost wages! Flu makes you miserable! And don’t forget, it is a DEADLY disease. On average 40,000 people die every year from the flu.

Most people do things every day that are only somewhat effective at preventing severe consequences, but they do them anyway on the off chance that it might prevent some freak occurrence from happening. For example: some people “always” buy organic because they think that it prevents cancer or is healthier (neither of these claims have evidence to back them up). Brushing your teeth everyday is kind of effective at preventing cavities, but it needs to be coupled with flossing, which a lot of people don’t do. Wearing your seat belt probably can’t prevent every death from catastrophic car accidents, yet most people never question these activities, despite the fact that they can not prevent all cavities or all car deaths or all cases of cancer. YET these same people will turn around and say that they wont get the flu vaccine because it is not effective against every strain of flu. It doesn’t really make any sense, at all.

Also, it’s not just whether you get sick or not. The most vulnerable members of our society need to be protected by us. It is a concept called herd immunity. You can spread germs to others who can’t get the shot even if you don’t get sick yourself. Examples of people who cannot get the flu shot are people who are immuno-compromised, very sick people, babies under 6 months, the elderly, people undergoing cancer therapy, and people who legitimately can’t get vaccines because of allergies.

Question: If I get a vaccine won’t that weaken my own immune system because I won’t be challenging it enough? What doesn’t kill you makes you stronger?

Answer: No. Most people don’t know that getting the shot actually does “work” your immune system. Just as hard as actually getting the flu from natural infection. It puts your immune system to work making antibodies against the virus, the EXACT same way as if you were infected, but without the miserable, costly or even deadly side effects.

Our immune systems are miraculous things. They fight off thousands of encounters with bacteria, viruses, and parasites every day. When you allow your self to get sick, you open yourself up to getting dangerous secondary infections (like pneumonia, bronchitis or rhinovirus). Because, influenza damages the ciliated cells of the upper respiratory tract, leading to decreased tracheal mucociliary velocity and clearance of other pathogens — and coughing rips up the throat, making you vulnerable to the common bacteria (and viruses) that live in our throat and around our nose. A lot of people that die during the flu season actually die from secondary infections. And god forbid you actually pick up a strain of bacteria that is antibiotic resistant, which many are now (!!) due to the over-use of antibiotics.

Question: I don’t want to get flu symptoms from the shot, and I’ve heard that if I get the vaccine I will feel sick.

Answer: You can’t get the flu from getting the shot.

That is a common misconception because vaccines used to be made with whole viruses that had been “weakened” (attenuated), they were still strong enough to make us feel sick. Today’s vaccines are made with just the smallest piece of virus possible, not the whole virus, therefore it is impossible to get sick from them. There is one exception: If you opt to get the nasal mist vaccine, that is made with “live attenuated” virus, so you can get some symptoms if you chose that delivery method over the shot.

Question: When should I get vaccinated?

Answer: CDC recommends that people get vaccinated against flu soon after vaccine becomes available, if possible by October.

It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against the flu.

Doctors and nurses are encouraged to begin vaccinating their patients soon after vaccine becomes available, preferably by October so as not to miss opportunities to vaccinate. Those children aged 6 months through 8 years who need two doses of vaccine should receive the first dose as soon as possible to allow time to get the second dose before the start of flu season. The two doses should be given at least four weeks apart.

Did I answer your question here? If not, please post your questions and I will do my best to answer them!

Founder | Scientist. Teacher. Author.