About 95% of those who have received two doses of the Sinovac vaccine have developed an immune response which prevents the spread of SARS-CoV-2, or COVID-19, according to research jointly conducted by the Thai Red Cross Emerging Infectious Diseases Health Science Centre of King Chulalongkorn Memorial Hospital and the US Armed Forces Research Institute of Medical Science (USAMD-AFRIMS).

The National Vaccine Institute said that 186 volunteers have joined the clinical trials, to test their immune response to the SARS-CoV-2 virus. All of them had received their second dose of Sinovac vaccine at least two before the trial.

Blood samples were drawn and tested with the live virus two weeks after the second dose and the result shows that more than 70% of the 171 volunteers had developed an immune response strong enough to prevent the spread of the virus in laboratory tests.

The National Vaccine Institute said there is no need for the general public to test their own immune response, noting that this is the responsibility of doctors to judge who should be tested after their vaccinations.

The institute also said the immune response may differ between individuals, depending on gender, underlying diseases or their immune system, adding that those who are fully inoculated must not lower their guard, to protect themselves from getting infected.

Meanwhile, the Disease Control Department revealed the common side effects, which emerged within 30 minutes and 24 hours of inoculation with Sinovac or AstraZeneca vaccines, between June 1^st and 21^st.

Side effects from Sinovac vaccine within the first 30 minutes:

• Weakened muscles                     4.7%
• Nausea                                           7.3%
• Muscle pains                                7.9%
• Headache                                      18.7%
• Pain/swelling at injection site  49.4%

Side effects after 24 hours:

• Pain/swelling at injection site   11.6%
• Fever                                               11.8%
• Fatigue                                           15.8%
• Headache                                       22.8%
• Muscle pain                                   23.6%

Side effects of AstraZeneca vaccine within the first 30 minutes:

• Pain/swelling at injection site   12.5%
• Fatigue                                            14.6%
• Muscle pain                                    19.1%
• Fever                                                21.1%
• Headache                                        21.4%

Side effects 24 hours one day afterward:

• Pain/swelling at injection site    9.9%
• Fatigue                                             12.7%
• Headache                                        19.7%
• Muscle pain                                     23%
• Fever                                                 24.8%