Events Supposedly Attributable to Vaccination and Immunization (ESAVI) can range from mild reactions to vaccines to adverse or coincidental events that occurred after vaccination.
It is important to note that not all events reported are actually caused by a vaccination. The only relation between two occurrences is that they happened around the same time. Also, it is probable that not all adverse events resulting from vaccination are reported.
Non-serious ESAVI
A non-serious ESAVI is one that does not endanger the life of the vaccinated person (or embryo, fetus, or newborn if the vaccinated person has been pregnant) that disappears without treatment or with symptomatic treatment, that does not require hospitalisation of the affected person, and does not cause a long-term disability or disorder.
Serious ESAVI
A serious ESAVI is one that meets any of the following conditions:
- Causes the death of the vaccinated individual.
- Poses an imminent danger to the life of the vaccinated individual.
- Requires hospitalisation or prolongs a hospital stay.
- Is a cause of persistent or significant disability or incapacity.
- Is suspected of having caused a congenital abnormality or stillbirth.
- Is suspected of having caused an abortion.
Source: Manual for Surveillance of Events Supposedly Attributable to Vaccination or Immunization in the Region of the Americas. Washington, D.C.: Pan American Health Organization; 2022. License: CC BY-NC-SA 3.0 IGO. https://doi.org/10.37774/9789275123867.
ESAVI are constantly monitored and documented by regulatory and health agencies around the world. The table below presents the frequency of some commonly reported ESAVI for the vaccines available in Trinidad and Tobago:
| Vaccine | Health Event (Global Frequency/Rate) | |
| Mild | Adverse | |
| Polio vaccines - Inactivated Poliomyelitis Vaccine (IPV) and Oral Poliomyelitis Vaccine (OPV) | In general, OPV is well tolerated by vaccine recipients. IPV - Injection site reactions include Injection site erythema (0.5-1%), Induration (hardening of skin) (3-11%), Tenderness (14-29%) | Vaccine-associated paralytic polio (1 per 2.9 per million doses), Aseptic meningitis/ encephalitis (Case reports only) None |
| Measles, Mumps, Rubella (MMR) | Measles - fever >103º/39.4 ºC (5 to 15%), rash (2% - 5%) | Measles - Anaphylaxis (3.5 to 10 per million doses), seizures (1 in 2000 to 3000), thrombocytopenia, Mumps - aseptic meningitis (1 to 20 cases per 100,000 doses depending on the vaccine strain), Rubella - acute joint symptoms (10%) |
| Diphtheria, Pertussis and Tetanus (DPT) | Systemic reactions such as fever over 38°C and irritability (40% to 75%), drowsiness (33% to 62%), loss of appetite (20% to 35%), and vomiting (6% to 13% | Persistent screaming (3.5 per 100) Hyporesponsive hypotonic episodes (57-250 per 100,000) Seizures ( 6 per 100,000), Encephalopathy ( 0.3 - 5.3 per 1,000,000) Anaphylaxis (1.3 per 1,000,000) |
| Pneumococcal | fever 39C (< 1%) | None proven to date |
| Hepatitis B (Hep B) | Pain(3-29 %), Erythema (3%) Swelling (3%), Temperature greater than 37.7°C (1-6%), Headache (3%) | Severe Anaphylaxis (1.1 per 106) |
| Varicella | Fever n(15%), Skin rash (3-5%) | Febrile seizures (with MMR via separate injection) (4 per 10,000) |
| HPV | Injection site related pain, swelling, and erythema Mild systemic adverse events possibly related to vaccination included headache, dizziness, myalgia, arthralgia, and gastrointestinal symptoms (nausea, vomiting abdominal pain) | Anaphylaxis (1.7 cases per million doses) Postural Orthostatic Tachycardia Syndrome (POTS), Chronic Regional Pain Syndrome (CRPS), Chronic Fatigue Syndrome (CFS) are reported as adverse events following HPV immunization, however, there is no causal association between these conditions and HPV immunization. |
Source: The World Health Organization Information Sheets on Observed Rates of Vaccine Reactions
