Vaccination to prevent influenza infection must be adjusted according to the type of influenza virus expected to circulate each year. At the end of March 2022, there was a change in the influenza strain from the Northern Strain to the Southern Strain, and the virus strains used to produce the vaccine were changed for 2 out of 4 strains as follows:
| 2021-2022 Northern Strain | 2022 Southern Strain |
| – Virus type A Victoria strain (H1N1) | – Virus type A Victoria strain (H1N1) |
| – Virus type A Cambodia strain (H3N2) | – Virus type A Darwin strain (H3N2) |
| – Virus type B Washington strain | – Virus type B Austria strain |
| – Virus type B Phuket strain | – Virus type B Phuket strain |
In Thailand, influenza outbreaks occur throughout the year but are more common during the rainy and winter seasons. Therefore, it is necessary to get vaccinated annually to boost immunity, and revaccination can be done within 6 months to 1 year.
Symptoms of Influenza
After infection, there is an incubation period of 1-4 days, followed by symptoms affecting both the upper and lower respiratory tracts. Common prominent symptoms include:
- High fever
- Muscle aches and severe fatigue
- Runny nose and cough
Influenza Situation in Thailand in 2021
In Thailand, the influenza situation in 2021 from January 1 to October 27 reported 9,314 cases nationwide, with an incidence rate of 14.05 per 100,000 population. Among these, 48% had symptoms of acute respiratory infection, which may include pneumonia or complications requiring hospitalization or resulting in death, especially in high-risk groups such as those with certain health problems and the elderly.
Effects on the Body When Infected with Influenza
- Respiratory epithelial cells are damaged, allowing secondary bacterial infections, which may cause middle ear infection or pneumonia
- Increased inflammation of blood vessels raises the risk of plaque rupture and blood vessel blockage, increasing the risk of heart and vascular events
- Bronchial inflammation can exacerbate lung diseases, asthma, and emphysema, leading to more severe symptoms
- Metabolic abnormalities occur; diabetic patients may experience higher blood sugar levels, worsening diabetes symptoms
- High fever causes dehydration, leading to kidney dysfunction
Who Should Get Vaccinated?
Because high-risk groups may experience severe symptoms or complications from influenza, including caregivers close to these groups, those who should receive the influenza vaccine include:
- Children aged 6 months and older
- Adults aged 65 years and older
- People with chronic diseases such as lung disease, asthma, heart disease, stroke, kidney failure, liver disease, cancer, diabetes, or immunocompromised individuals
- People with a BMI over 35 or weighing more than 100 kilograms
- People with brain disabilities who cannot care for themselves
- Pregnant women at 4 months gestation or more
- Healthcare personnel and laboratory staff
- People traveling abroad to countries such as the United States, Europe, China, and countries with influenza outbreaks
Benefits of Influenza Vaccination
- Prevents influenza by 70 to 90%
- Reduces middle ear infections in children by 36%
- Prevents influenza in elderly people over 65 years by 60%
- Reduces mortality from influenza in elderly people over 65 years by 70 to 80%
Benefits of Influenza Vaccination in Diabetic Patients
- Reduces hospital admissions by 79%
- Reduces complications by 56%
- Reduces death from influenza infection by 28%
Benefits of Influenza Vaccination in Heart Disease Patients
- Reduces death from influenza infection by 75%
- Reduces cardiovascular events by 30%
- Reduces stroke incidence by 24%
Click Influenza Vaccine Program for New Strains 2022
Click Vaccination Guidelines for Adults and the Elderly
