The ?Green Channel? of the Veneto region as a model for vaccine safety monitoring in Italy

Advancing the Science of Vaccine Safety During the Coronavirus Disease 2019 (COVID-19) Pandemic and Beyond: Launching an International Network of Special Immunization Services

Within 2 years after the start of the coronavirus disease 2019 (COVID-19) pandemic, novel severe acute respiratory syndrome coronavirus 2 vaccines were developed, rigorously evaluated in large phase 3 trials, and administered to more than 5 billion individuals globally. However, adverse events of special interest (AESIs) have been described post-implementation, including myocarditis after receipt of messenger RNA (mRNA) vaccines and thrombosis with thrombocytopenia syndrome after receipt of adenoviral vector vaccines. AESIs are rare (<1 to 10/100 000 vaccinees) and less frequent than COVID-19 complications, though they have associated morbidity and mortality. The diversity of COVID-19 vaccine platforms (eg, mRNA, viral vector, protein) and rates of AESIs both between and within platforms (eg, higher rate of myocarditis after mRNA-1273 vs BNT162b2 vaccines) present an important opportunity to advance vaccine safety science. The International Network of Special Immunization Services has been formed with experts in vaccine safety, systems biology, and other relevant disciplines to study cases of AESIs and matched controls to uncover the pathogenesis of rare AESIs and inform vaccine development.

True and false contraindications to vaccines

Nowadays, the awareness of risks related to infectious diseases has decreased, whereas THE perception of risks related to vaccination is growing. Therefore, it may be difficult for health care providers to convince people of the importance of vaccination and adherence to the immunisation schedule. Selected situations that might raise uncertainties about vaccine recommendations are discussed in order to help health care providers to identify real and perceived contraindications to vaccines, and cases to be referred to specialised pre-vaccination consultation due to an increased risk of adverse events to vaccines.

Immunizing Patients With Adverse Events After Immunization and Potential Contraindications to Immunization: A Report From the Special Immunization Clinics Network

BACKGROUND

For patients who have experienced adverse events following immunization (AEFI) or who have specific medical conditions, there is limited evidence regarding the best approach to immunization. The Special Immunization Clinics (SICs) Network was established to standardize patient management and assess outcomes after reimmunization. The study objective was to describe the first 2 years of the network's implementation.

METHODS

Twelve SICs were established across Canada by infectious diseases specialists and allergists. Inclusion criteria were as follows: local reaction ≥ 10 cm, allergic symptoms < 24 hours postimmunization, neurologic symptoms and other AEFI or medical conditions of concern. Eligible patients underwent a standardized evaluation, causality assessment was performed, immunization recommendations were made by expert physicians and patients were followed up to capture AEFI. After individual consent, data were transferred to a central database for analysis.

RESULTS

From June 2013 to May 2015, 151 patients were enrolled. Most were referred for prior AEFI (132/151, 87%): 42 (32%) for allergic-like reactions, 31 (23%) for injection-site reactions, 20 (15%) for neurologic symptoms and 39 (30%) for other systemic symptoms. Nineteen patients (13%) were seen for underlying conditions that complicated immunization. Reimmunization was recommended for 109 patients, 60 of whom (55%) were immunized and followed up. Eleven patients (18%) experienced recurrence of their AEFI; none were serious (eg, resulting in hospitalization, permanent disability or death).

CONCLUSIONS

The most frequent reasons for referral to a SIC were allergic-like events and injection site reactions. Reimmunization was safe in most patients. Larger studies are needed to determine outcomes for specific types of AEFI.

Overview of the Clinical Consult Case Review of adverse events following immunization: Clinical Immunization Safety Assessment (CISA) network 2004-2009

BACKGROUND

In 2004 the Clinical Consult Case Review (CCCR) working group was formed within the CDC-funded Clinical Immunization Safety Assessment (CISA) Network to review individual cases of adverse events following immunizations (AEFI).

METHODS

Cases were referred by practitioners, health departments, or CDC employees. Vaccine Adverse Event Reporting System (VAERS) searches and literature reviews for similar cases were performed prior to review. After CCCR discussion, AEFI were assessed for a causal relationship with vaccination and recommendations regarding future immunizations were relayed back to the referring physicians. In 2010, surveys were sent to referring physicians to determine the utility and effectiveness of the CCCR service.

RESULTS

CISA investigators reviewed 76 cases during 68 conference calls between April 2004 and December 2009. Almost half of the cases (35/76) were neurological in nature. Similar AEFI for the specific vaccines received were discovered for 63 cases through VAERS searches and for 38 cases through PubMed searches. Causality assessment using the modified WHO criteria resulted in classifying 3 cases as definitely related to vaccine administration, 12 as probably related, 16 as possibly related, 18 as unlikely related, 10 as unrelated, and 17 had insufficient information to assign causality. The physician satisfaction survey was returned by 30 (57.7%) of those surveyed and a majority of respondents (93.3%) felt that the CCCR service was useful.

CONCLUSIONS

The CCCR provides advice about AEFI to practitioners, assigns potential causality, and contributes to an improved understanding of adverse health events following immunizations.