The study was conducted in collaboration with the Prince of Songkla University’s Faculty of Medicine and funded by the National Research Council of Thailand.
“We divided 95 candidates aged 18 to 60 who had received two Sinovac jabs into three groups. The first group of 30 received one full dose [0.5ml] of the AstraZeneca vaccine using the IM method,” the department’s director-general Dr Supphakit Siriluck said.
“The second group of 31 received a fifth [0.1ml] of the AstraZeneca jab via the ID method four to eight weeks after they received their second shot of Sinovac. The rest of the participants also received a fifth of the AstraZeneca dose via the ID method, but eight to 12 weeks after their second jab.”
Supphakit said 14 days after receiving the booster, the first group’s immunity level rose to 1,653AU (arbitrary unit), while that of the second and third groups rose to 1,300.5AU on average. Before receiving the booster, the participants’ average immunity level was 128.7AU.
The study also found that the intradermal injection of the vaccine also raised the recipients’ immunity against the Delta variant of the virus to 234.4AU from the original 16.3AU after two Sinovac shots.
“The intradermal approach also caused fewer side effects, as in significantly less skin irritation, muscle ache, headache, fatigue and shivering compared to the intramuscular approach,” he said.
“Since the ID application requires only a fifth of a normal dose to achieve similar results, it can help boost the rate of vaccination in areas where supplies are limited,” he added. “However, more skilled medics are required for the ID approach as the needle has to be angled 10 to 15 degrees and only pushed 1mm under the skin. The department is planning to pilot the ID method in areas where there are enough skilled medics like Phuket.”
Published : September 23, 2021