Safety and efficacy of intramuscular vaccination without aspiration before injection: a randomized clinical trial

INTERVENTION: Experimental group: 71 subjects (men or women) will receive one dose of Hepatitis A vaccine (adult) at 1 mL intramuscularly in the ventrogluteal region, without aspiration (syringe plunger retraction), to verify blood return before injecting the immunobiological into the muscle. Control group: 71 subjects (men or women) will receive one dose of Hepatitis A vaccine (adult) at the 1 mL intramuscularly in the ventrogluteal region, with aspiration (syringe plunger retraction), to verify blood return before injecting the immunobiological into the muscle. Injections, Intramuscular Procedure/surgery Vaccination CONDITION: Drug‐Related Side Effects and Adverse Reactions Drug‐Related Side Effects and Adverse Reactions. Signals e Symptons. ; Drug‐Related Side Effects and Adverse Reactions ; Signs and Symptoms Signs and Symptoms PRIMARY OUTCOME: Expected outcome 1: occurrence of equal or lesser incidence of post‐vaccination adverse events, evaluated through inspection, palpation of the injection site, temperature measurement by means of an infrared sensor thermometer and verbal report of symptoms by the participant, daily, for three consecutive days and on the thirtieth day after vaccination. Expected outcome 2: seroconversion of antibodies against Hepatitis A virus, evaluated by venous blood collection, chemiluminescent laboratory testing, and anti‐HAV (anti‐hepatitis A virus) immunoglobulin (IgG) serum levels equal to or greater than 10 mlU / mL, analysis performed before the intervention and thirty days after. SECONDARY OUTCOME: Secondary outcome 1: decreased pain during vaccination, assessed by the numerical scale of pain intensity (NDT), which assigns points from 0 to 10 to the pain, with 0 being no pain and 10 being the worst possible pain. Secondary outcome 2: Heartbeat within the normal range (60 to 100 beats per minute ‐ ppm), assessed by a digital pulse oximeter device placed on the participant, recorded one minute before, immediately after administration of the vaccine and five minutes later . Secondary outcome 3: peripheral oxygen saturation greater than or equal to 95%, assessed by digital pulse oximeter device placed on the participant and recorded one minute before, immediately after administration of the vaccine and five minutes later. INCLUSION CRITERIA: Healthy volunteers; both genders; age between 18 and 59 years.