On behalf of the Infectious Diseases Committee
of the Society of Obstetricians and Gynaecologists of Canada
Date: April 1st, 2021
Reports have emerged from Europe documenting extremely rare events of arterial and venous thrombosis associated with low platelets following the AstraZeneca/COVISHIELD adenovirus vector COVID-19 vaccines. There have been no cases reported in Canada.
The observed condition is being called by some hematologists “vaccine-induced prothrombotic immune thrombocytopenia” (VIPIT). This syndrome has not yet been proven to be vaccine induced but has been observed in persons receiving the vaccine within 4-20 days. The actual rate of occurrence is unclear as all data from global observations are not yet available. It appears to be extremely rare, occurring in anywhere from 1 in every 125,000 to 1 in 1 million people following AstraZeneca/COVISHIELD COVID-19 vaccines.1, 2, 3 Most cases have occurred in women <55 years of age, however, this may reflect a bias to women receiving the vaccine more than men in this age group because of the decision to prioritize front-line health care workers. There is no known association between this syndrome and pregnancy. With an abundance of caution, until further data is available, Canada has paused use of the AstraZeneca/COVISHIELD COVID-19 vaccines for individuals <55 years of age. Until the nature of these events is further examined, the SOGC does not recommend the use of AstraZeneca/COVISHIELD COVID-19 vaccines for individuals <55 years of age keeping in line with current National Advisory Committee of Immunization (NACI) and Health Canada recommendations.3, 4
It is important to note that the thrombotic events observed in association with the AstraZeneca/COVISHIELD COVID-19 vaccines are an extremely rare and, given the number of doses given to pregnant women at this point, it is statistically unlikely that a prenatal provider in Canada will have to identify or manage a case of vaccine-induced prothrombotic immune thrombocytopenia (VIPIT). If you suspect VIPIT, a diagnosis and management algorithm has been proposed by the group at Science Table (COVID-19 Advisory for Ontario) and is available on their website.5 Given the unique physiologic and hematologic characteristics of pregnancy, we advise urgent consultation with hematology prior to administration of anticoagulants if VIPIT is being considered.
Importantly, these rare adverse events have not been described for mRNA vaccines and appear not related to the spike protein. Pregnant women can continue to be vaccinated using mRNA vaccines as they become eligible according to the jurisdictional eligibility schemes.
References
1. Covid-19 vaccine astrazeneca: Benefits still outweigh the risks despite possible link to rare blood clots with low blood platelets. European Medicines Agency. 2021. Available at https://www.ema.europa.eu/en/news/covid-19-vaccine-astrazeneca-benefits-still-outweigh-risks-despite-possible-link-rare-blood-clots.
2. Covid-19 vaccine astrazeneca – safety assessment result: The vaccine is safe and effective in the fight against covid-19. Paul-Ehrlich-Institut. 2021. Available at https://www.pei.de/EN/newsroom/hp-news/2021/210319-covid-19-vaccine-astrazeneca-safety-assessment-result-vaccine-safe-and-effective.html;jsessionid=734B77911C71AA454CCA874524CE23E1.intranet211.
3. Naci rapid response: Recommended use of astrazeneca covid-19 vaccine in younger adults. Health Canada. 2021. Available at https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/rapid-response-recommended-use-astrazeneca-covid-19-vaccine-younger-adults.html.
4. Health canada taking further action to confirm the benefit-risk profile of the astrazeneca vaccine. Health Canada. 2021. Available at https://www.canada.ca/en/health-canada/news/2021/03/health-canada-taking-further-action-to-confirm-the-benefit-risk-profile-of-the-astrazeneca-vaccine.html.
5. Vaccine-induced prothrombotic immune thrombocytopenia (vipit) following astrazeneca covid-19 vaccination. Science Table: COVID-19 Advisory for Ontario. 2021. Available at https://doi.org/10.47326/ocsat.2021.02.17.1.0.
To read the statement, click HERE