One way to help stop the COVID-19 outbreak is for the majority of people worldwide to be vaccinated. Today, we will introduce the types and importance of vaccines.
Vaccine Production Technology
COVID-19 vaccines have various production technologies, which can be divided into 2 main groups:
- Vaccines containing genetic material (DNA or RNA) as components. These vaccines stimulate immunity by introducing the virus’s genetic material into the recipient’s cells to decode the genetic information. This group includes live attenuated virus vaccines, recombinant virus vector vaccines, RNA-based vaccines, and DNA-based vaccines.
- Vaccines that do not require a carrier to stimulate immunity because they are produced from inactivated viruses or viral proteins in various forms, which can stimulate the body’s immune response without passing through the recipient’s cells. This group includes recombinant protein subunit vaccines, virus-like particle vaccines, synthetic peptide vaccines, inactivated virus vaccines. Due to different production technologies, vaccines have different advantages and limitations.
COVID-19 Vaccines Available in Thailand
Currently (as of April 2021), there are 2 types of vaccines imported into Thailand:
- COVID-19 Vaccine AstraZeneca (recombinant virus vector vaccine) which uses another virus as a carrier, produced by Oxford–AstraZeneca, United Kingdom. The injection is given intramuscularly at 0.5 milliliters per dose, with a total of 2 doses spaced about 4-12 weeks apart. It is recommended for people aged 18 and over. Studies in the elderly over 65 years old show good immune response stimulation. The World Health Organization and Thailand have approved its use in the elderly. Overall efficacy prevents symptomatic infection by 70.4% and prevents severe COVID-19 symptoms by 100%.
- CoronaVac or Sinovac COVID-19 vaccine (Inactivated Vaccine) is an inactivated virus vaccine produced by Sinovac, People’s Republic of China. The injection is given intramuscularly at 0.5 milliliters per dose, with a total of 2 doses spaced about 2-4 weeks apart. It is designated for people aged 18-59. Studies in those over 60 years old show that it stimulates immunity as effectively as in younger people, with similar side effects. The overall efficacy in preventing symptomatic infection from preliminary data analysis in various countries is Indonesia 65.3%, Turkey 91.25%, Brazil 77.9%. Overall efficacy is 100% in preventing severe COVID-19 symptoms. Vaccination cannot completely prevent infection but can reduce disease severity and mortality rates.
Who Should Get Vaccinated
Everyone should receive the COVID-19 vaccine, but while vaccine supplies are limited, the Department of Disease Control, Ministry of Public Health, has prioritized vaccination for high-risk groups, including:
- Frontline medical and public health personnel in both public and private sectors
- People with underlying diseases such as chronic respiratory diseases, cardiovascular diseases, stage 5 chronic kidney disease, stroke, diabetes
All types of cancer patients undergoing chemotherapy, radiotherapy, and immunotherapy
- People aged 60 and over
- Personnel involved in COVID-19 control such as village health volunteers, military, police who must screen people entering from abroad and in outbreak areas
Contraindications and Precautions Before Vaccination
- People with a history of allergy to any vaccine components
- People with fever or illness should postpone vaccination
Preparation Before Receiving the Vaccine
- Vaccine recipients should prepare physically and mentally, relax to reduce adverse reactions from vaccination. If in doubt, ask the staff for information.
- Drink enough water and avoid tea and coffee
Side Effects After Vaccination
Common symptoms include pain, swelling, itching, redness at the injection site. Other symptoms may include fatigue, nausea, vomiting, muscle aches, headache, or fever. Most symptoms are mild and resolve within 1-2 days. For mild symptoms such as fever or headache, paracetamol can be taken to relieve symptoms.
Severe but rare symptoms include high fever, chills, severe headache, rash all over the body, facial swelling, neck swelling, difficulty breathing, palpitations, dizziness or weakness, or weakness in limbs. Almost all symptoms improve and return to normal quickly. If severe symptoms occur, see a doctor immediately.
Post-Vaccination Care
- After vaccination, recipients must be observed at the healthcare facility for at least 30 minutes to monitor for possible side effects and report any symptoms to the attending doctor or nurse.
- Continue to monitor symptoms at home. If side effects occur, consult a doctor or healthcare facility where the vaccine was received.
- Receive vaccines as scheduled and keep vaccination records as proof.
Reference: Department of Disease Control, Ministry of Public Health. COVID-19 Vaccination Guidelines in the 2021 Outbreak Situation in Thailand. February 2021
Dr. Renuka Charaspongpisut
Specialist in Pediatric Neurology
Child and Adolescent Health Center, Phyathai 2 Hospital
