Table 4. The comparison of Pfizer vaccine side effects after first and second doses.
*p-value significant as <0.05
| Variable | Side effects after first dose | Side effects after second dose | p-value | ||
| Yes, n(%) | No, n(%) | Yes, n(%) | No, n(%) | ||
| Pain at injection site | 632(63.2%) | 368(36.8%) | 576(57.6%) | 424(42.4%) | <0.001* |
| Swelling at injection site | 528(52.8%) | 472(47.2%) | 528(52.8%) | 472(47.2%) | 0.462 |
| Redness at injection site | 180(18.0%) | 820(82.0%) | 104(10.4%) | 896(89.6%) | <0.001* |
| Lymphadenopathy | 432(43.2%) | 568(56.8%) | 436(43.6%) | 564(56.4%) | <0.001* |
| Fever (temperature >37.8 ˚C) | 700(70.0%) | 300(30.0%) | 424(42.4%) | 576(57.6%) | <0.001* |
| Headache | 436(43.6%) | 564(56.4%) | 448(44.8%) | 552(55.2%) | <0.001* |
| Nausea | 200(20.0%) | 800(80.0%) | 96(9.6%) | 904(90.4%) | <0.001* |
| Rashes | 452(45.2%) | 548(54.8%) | 608(60.8%) | 392(39.2%) | <0.001* |
| Burning at injection site | 704(70.4%) | 296(29.6%) | 580(58.0%) | 420(42.0%) | <0.001* |
| Flu-like illness | 272(27.2%) | 728(72.8%) | 176(17.6%) | 824(82.4%) | <0.001* |
| Anxiety | 308(30.8%) | 692(69.2%) | 424(42.4%) | 576(57.6%) | <0.001* |
| Muscle pain | 632(63.2%) | 368(36.8%) | 628(62.8%) | 372(37.2%) | <0.001* |
| Fatigue | 372(37.2%) | 628(62.8%) | 376(37.6%) | 624(62.4%) | <0.001* |
| Joint pain | 580(58.0%) | 420(42.0%) | 456(45.6%) | 544(54.4%) | <0.001* |
| Chills | 460(46.0%) | 540(54.0%) | 456(45.6%) | 544(54.4%) | <0.001* |
| Cough | 380(38.0%) | 620(62.0%) | 196(19.6%) | 804(80.4%) | <0.001* |
| Sore throat | 528(52.8%) | 472(47.2%) | 196(19.6%) | 804(80.4%) | 0.029* |
| Shortness of breath | 300(30.0%) | 700(70.0%) | 452(45.2%) | 548(54.8%) | <0.001* |
| Diarrhea | 376(37.6%) | 624(62.4%) | 328(32.8%) | 672(67.2%) | <0.001* |
| Chest pain | 304(30.4%) | 696(69.6%) | 368(36.8%) | 632(63.2%) | <0.001* |