Influenza, abbreviated as influenza, is a viral acute respiratory infection caused primarily by the common influenza virus in the population and spreads throughout the world. Seasonal epidemics of influenza are estimated to cause influenza in 5-10% of adults and 20-30% of children globally each year, resulting in 3-5 million severe cases and 250,000-500,000 deaths.

The seasonal influenza affecting human health as of today are type A (A) and type B (B). Influenza A viruses are further categorized into subtypes based on the combination of two different kinds of viral surface proteins (hemagglutinin (H) and neuraminidase (N)). For example, influenza A viruses that are spreading on the earth are the H1N1 and H3N2 seasonal influenza subtypes, as well as the human infection of H7N9 avian influenza, which was first detected and reported in China in 2013. Only influenza A viruses can cause an influenza pandemic, and the 2009 influenza pandemic was caused by the influenza A H1N1 virus. Influenza B viruses do not have subtypes and are divided into two major groups (lineages), the Yamagata B lineage and the Victoria B lineage.

Dr. Clove is here to answer that question.

Contents refer to Dr. Clove's popular science article: "307 people died in Hong Kong's flu outbreak! 4 Things You Need to Know About Influenza".

Author / Shi Han丨Dr. Clove Cloud Clinic

Editor / Lee Bad

At the peak of the summer vacation, many parents may be ready to take their children to Hong Kong to play a round, but recently to Hong Kong really need to pay attention! Since May this year, we have entered the summer influenza outbreak period. Influenza in Hong Kong is generally in January - March, July - August is more common, but this year advanced to May.

The Department of Health of Hong Kong announced that from May 5 to August 2, less than three months, a total of 14,713 people were diagnosed with influenza, of whom 450 suffered from severe influenza and 307 died. One of the most common descriptions used by the major media is that the number of deaths exceeded that of Hong Kong during the SARS outbreak, so the impact of this influenza can be imagined.

It is reported that the influenza outbreak was mainly concentrated in nursing homes, accounting for 52% of the total, because of the ageing population and the greater chance of serious complications due to infection of the elderly. This was followed by kindergartens and child care centers, which accounted for 22.8% of the total.

The summer outbreak was dominated by influenza A (H3N2), with patients showing symptoms of common influenza, sometimes with diarrhea and vomiting, and in severe cases with pneumonia and respiratory failure, or even death. Influenza viruses are mainly transmitted through droplets produced by patients' coughing, sneezing or talking, and also through direct contact with patients' secretions.

Thankfully, however, the flu's activity has dropped slightly over the past week, but it's still not something to be taken lightly. Netizens for this also have lamented: is preparing to go to Hong Kong it! Airfare hotel annual leave oh are ready!

Why do you still get the flu after getting the flu shot?

Data released by the Department of Health of Hong Kong show that among the deaths, 137 (45.1%) of the 304 adult deaths had received influenza vaccination. After receiving influenza vaccination, why did they still get influenza and even die?

Each year's flu is made up of a different strain of virus, and the effectiveness of the flu prevention vaccine changes from year to year. So if the vaccine was given 2 years ago, the effectiveness will drop to a very low level and immunity will be lost. And people who had been vaccinated against the flu last year are limited to a flu vaccine that is only effective for about 6 months. Even so, getting vaccinated is still the primary and only means of preventing the flu from occurring.

What are the symptoms of the flu?

Normally healthy children who are infected with the flu virus may have a mild case of influenza, which is no different from the common cold, but is more contagious and usually resolves in 2 to 3 days.

The typical flu, on the other hand, comes on mostly suddenly, from head to toe, and may show the following symptoms:

• Fever: It usually lasts for 3 to 5 days, and the temperature can be as high as 39-40°C. There may be chills, chills, cold hands and feet, and headache. The younger the child, the less it will be expressed and may just be irritable, crying, etc.

• Eye manifestations: Many children also have tearing, eye droppings or slightly bloodshot eyes. If your child shows these signs, don't think it's just conjunctivitis, and don't categorize these abnormalities as "fire".

• Symptoms of rhinitis: nose rubbing; sneezing; runny nose, which can easily become 'boogers' if there is not a lot of snot; nasal congestion, which in small children may be characterized by crying, huffing and puffing, open-mouthed breathing or snoring.

• Uncomfortable throat: Older children will report a dry, itchy, sore throat, while younger children may show more crying or a fear of food, especially solid foods.

• Cough: Mostly paroxysmal, not a constant cough. The number of coughs at a time may not be a lot, but it will be more frequent. It is also mostly dry.

• Other discomforts: Older children may report generalized muscle and joint aches and weakness. Younger children are prone to crying and clinginess.

All of these symptoms may be present, but not always. The younger the child, the more atypical the symptoms tend to be.

It's not the flu that's scary, it's the complications

In an average person, the flu will clear up in 3-7 days, with coughing and recovery of strength taking up to a week. But it is serious if there are complications of the flu, such as: laryngitis, acute otitis media, bronchitis, pneumonia and other more serious diseases.

Severe influenza is a sinister condition, often accompanied by pneumonia and respiratory distress, which is the leading cause of death from influenza.

No amount of treatment is better than early prevention.

1. Keep indoor air circulating and avoid going to crowded places during the peak of the epidemic.

2. Tissues should be used when coughing and sneezing to avoid droplet transmission.

3. Wash hands frequently and thoroughly to avoid dirty hands touching the mouth, eyes and nose.

4. Seek medical attention if you develop flu-like symptoms during an epidemic, and reduce contact with others and try to rest at home.

5. Influenza patients should be placed in respiratory isolation for 1 week or until major symptoms disappear. Patient utensils and secretions should be thoroughly sterilized.

6. Strengthen outdoor physical exercise to improve the body's ability to resist disease.

7. Prevention and control of outbreaks in institutions: When influenza is already prevalent in the community, two or more people in the same institution should be alerted to the presence of influenza-like symptoms within 72 hours and should be actively tested for pathogenicity. Once the diagnosis is confirmed, patients should be required to be hospitalized or recuperate at home, improve personal hygiene, and avoid and minimize contact with others.

8. Influenza vaccination: Influenza vaccination is the most effective means of preventing influenza and its complications that cannot be replaced by other methods. The vaccine needs to be administered annually for effective protection, and the replacement of the vaccine strain is decided by WHO based on global surveillance results.

All those years you've had the flu

SARS (Severe Acute Respiratory Syndrome)

The outbreak of SARS in 2003 swept across China, with the first case appearing in November 2002 in Foshan, Guangdong Province, and rapidly developing into an epidemic. With a cumulative total of 5,327 cases and 349 deaths in mainland China, its impact has broken through to the public healthcare and sanitation sectors.

I remember the days when whenever someone coughed, the people around them got uneasy. There was a time when everyone traveled with a mask. It was also rumored that boiling vinegar and drinking Banlangen could prevent strange diseases, leading to a rush to buy rice vinegar and Banlangen on the market.

Although it was later confirmed that these were just rumors, there were still many people who even went to Hong Kong to buy vinegar, and there were also people who spent $200 to $300 to acquire a bottle of vinegar.

avian influenza

Avian influenza, full name avian influenza, is an infectious disease of animals caused by a virus that usually only infects birds, and in rare instances, infects

Hogs.

In early 2004, avian influenza swept through the United States and parts of Asia, sickening and killing millions of poultry in China, Japan, Vietnam and other countries, and many people may have died as a result of infection with the avian influenza virus. Transmission occurs through a variety of routes, including the digestive tract, the respiratory tract, skin lesions and the conjunctiva of the eyes.

H7N9 avian influenza

H7N9 avian influenza, a new type of avian influenza, was first detected in late March 2013 in Shanghai and Anhui Province. H7N9 avian influenza is the first new subtype of influenza virus to be detected globally, and has not yet been included in China's statutory surveillance and reporting system for reporting infectious diseases, and as of early April 2013, a vaccine had not yet been introduced.

Infection with the virus is characterized by early onset of symptoms such as fever, and as of April 2013 it had not been confirmed that the virus is human-to-human transmissible. As of January 25, 2015 , 133 people have been diagnosed nationwide, 37 have died and 76 have recovered.

Chickens became the biggest trigger at that time, and none of them could be found in the grocery stores, and many people were afraid to eat chickens or even eggs during that time.

Hello. This year, Hong Kong's summer influenza is really serious, the number of consultations exceeded 10,000, nine times more than last year. According to the relevant information in Hong Kong, on the 3rd of this month, 5106 people sought treatment in public hospitals in Hong Kong, and on the 4th of this month, 5137 people sought treatment. As of the 3rd of this month, the summer flu has accumulated 439 serious cases in adults, of which 312 died. There were 19 severe cases in children, with 3 deaths. Most of them were infected with Influenza H3 A this time. Hong Kong is now experiencing a slight relief from influenza after a number of efforts.

Influenza A (H3) has struck tens of thousands of people, and it is not surprising that the number of deaths is higher than that of SARS in 2003. Nowadays, various mutated viruses continue to form, which is a challenge for human beings and scientists in the future. Hong Kong is a densely populated city with cramped housing and poor air circulation, which is an indirect source of influenza virus transmission. As a final word of caution, we advise you to wear a mask when traveling to Hong Kong during the summer flu season!

Influenza has never been an easy disease to deal with, as the "Spanish Flu" of 1918 killed about 20-40 million people worldwide! The current annual influenza pandemic causes 3-5 million cases of severe illness and 250,000-500,000 deaths worldwide.

In Hong Kong, influenza also frequently causes death.

In the winter flu season of 2015, there were 647 adult severe flu cases in Hong Kong, including 501 deaths, and 18 pediatric severe flu cases, including one death.

In the 2015 summer influenza season, 183 adult severe influenza cases were reported in Hong Kong, including 133 deaths; 4 pediatric severe influenza cases were reported (no deaths).

During the 2016 winter flu season, there were 409 adult severe flu cases in Hong Kong, including 211 deaths, and 27 pediatric severe flu cases, including 3 deaths.

During the 2017 winter influenza season, there were 66 cases of severe influenza in adults in Hong Kong, including 41 deaths, and 8 cases of severe influenza in children, including 1 death.

Influenza is an acute viral infection that spreads easily from person to person and can infect anyone in any age group. Influenza is a serious public health problem, and while most people recover within a week without seeking medical attention, with fever and other symptoms disappearing, influenza can cause serious illness and death in at-risk populations.

Annual influenza epidemics can severely affect all populations, with hospitalizations and deaths occurring mainly in high-risk groups, with the highest risk of complications among pregnant women, children aged 6-59 months, the elderly, people with chronic diseases (HIV/AIDS, asthma, chronic heart and lung diseases, etc.) and health-care workers. The majority of influenza-related deaths in developed countries and regions occur in people aged 65 years and older. The vast majority of influenza-associated deaths occur in developing countries, but there are currently no data to estimate the proportion of influenza in child mortality, particularly in developing countries.

Seasonal influenza spreads easily and can spread rapidly in crowded places such as schools and nursing homes. When an infected person coughs or sneezes, droplets containing the virus (i.e., infectious droplets) enter the air and transmit the virus to those around them who inhale these droplets. The virus can also be spread by infected hands.

Annual flu vaccination is the most effective way to prevent the flu.

Let's not talk about the fact that viruses mutate constantly, resulting in the transmission of diseases as well as the onset of illnesses caused by the failure of vaccines to keep up with them.

First of all, in fact, the number of deaths we have every year due to infectious diseases is quite alarming. To give a past figure, take the data released by the Ministry of Health in 2011, from June 1 to June 30, 2011, nationwide (excluding Taiwan, Hong Kong and Macao), 823,318 cases of statutory infectious diseases were reported, and 1522 cases of deaths were recorded (the data is quoted from a report on the People's Daily Online on July 11, 2011).

Over a month and a thousand people across the country!

The fact that humans are more numb to things that happen on a regular basis is a lot scarier than the number of deaths caused by a minor disaster!

So, when a virus breaks out (SARS, MERS, Ebola), people don't know about it and panic arises because it's a new topic with newsworthy content and the media is clamoring for it, leading to a moment of panic, and it's perceived as a powerful virus!

In fact, these pathogenic viruses, which are spreading every day, the key is to do a good job of personal hygiene, develop a good habit of hand washing, running water to wash hands or use hand sanitizing products to disinfect hands.

The World Health Organization repeatedly suggests that attention to hand hygiene can prevent more than 90% of infectious diseases!

It is recommended that the National People's Congress, the "development of hand hygiene habits" included in the quality of kindergarten education, from childhood to grasp the personal hygiene habits, to reduce the harm caused by infectious diseases!

The city of Shenzhen, through a motion of the city's National People's Congress (NPC), started to promote hand hygiene education in kindergartens in the city a few years ago!

With regard to this summer flu in Hong Kong, I would like to first popularize the fact that flu is different from common cold. Just as in the 1980s, when we listened to the news, we could always hear about how many people died of influenza in the United States, and at that time, most of us in the country found it unbelievable. There are always people who exclaim: How can Americans be so weak that a cold can kill so many people? In fact, this is really a wrong understanding of the disease, we had doubts because we were backward, do not understand the specifics. The flu does kill when it's severe. Today I'm going to explain the difference between the flu and the common cold. Below is a report of a flu test I prescribed today for a patient who, thankfully, was not sick with the flu.

1. Different pathogens of infection

Common cold viruses include respiratory syncytial virus, adenovirus, parainfluenza virus, rhinovirus, etc. Influenza viruses are categorized into A, B, and C, with A and B viruses being the most common.

2. Symptoms of infection are different

Common cold symptoms are mild, such as sneezing, runny nose, nasal congestion and other symptoms. The symptoms of influenza are significantly worse, manifested as headache, chills, dry cough, sore throat, sudden rise in body temperature, general malaise and muscle or joint pain, the severity of the symptoms that is certainly much heavier than the common cold.

3. The consequences are different

Common cold patients generally do not produce serious complications, and in a few cases can be combined with bacterial infections. But influenza patients will be seriously complicated by pneumonia, bronchitis and other diseases, induced asthma exacerbation, congestive heart failure, etc., and in severe cases, death occurs, and the mortality rate is significantly higher than that of the common cold.

4. Is the flu vaccine 100% effective?

The flu vaccine is not effective for everyone. The flu vaccine is 70% to 80% effective in healthy adults, and may be even less effective in older adults. It should also be noted that it takes 3-4 weeks for antibodies in the body to reach an effective level of protection after the flu vaccine is administered, and people with weak resistance and who are exposed to the flu virus may still get the flu during this 3-4 week period. The normal flu vaccine only protects for one year.

5. Who cannot get the flu vaccine?

Patients who have suffered from Guillain-Barre Syndrome or neurally demyelinating lesions are also not suitable for vaccination. In addition, people with advanced cancer, cardiorespiratory failure and ill health should be cautious or consult their doctors before deciding whether or not to receive the vaccination, and people who have recently undergone immunosuppressive treatment should not receive the vaccination immediately.