12月13日至9月11日，总接种21 millions，共673例严重不良反应，10万分之3.2。其中每十万剂疫苗发生严重不良反应：辉瑞2.4，Moderna: 3.9, AZ：9.8。大约68.5%的不良反应由第一针引发，21.4%与第二针有关。
673位严重不良反应患者中有667位住院治疗，在提交报告时，232位病人已经康复出院，304位仍在治疗，总结报告见表4。
阿斯利康疫苗共发生21例血小板减少症（TTS)，与上周报告无变化。2.4 / 10万 = 1 / 41000，其中16例确诊由疫苗诱导的免疫性血小板减少症(VITT)，1.9 / 10万 = 1 / 54000, 5例确诊与疫苗无关。一例VITT患者死亡报告，死因正在调查，尚未确定。
截止9月11日，安大略省已收到 369 例在接受 COVID19 mRNA 疫苗后出现心肌炎或心包炎的报告，比上周增加38例。其中208例，占56.4%，需要住院治疗。辉瑞207例，莫德纳162，274例男性，95例女性，男性占74.3%。年龄范围在 12 至 81 岁之间（中位数为 24 岁）； 症状多发生于青少年和轻年男性（18 - 24岁），更常见于第二针后一周之内，通常在4 - 5天。比率为18.5/million mRNA 疫苗；最高比率出现在接种第二针的18-24岁男性，168.7/million。
共有34人死亡暂时可能与疫苗相关，其中6人是老人院成员。5例死亡与严重不良反应有关，其中3例主要由其他基础病引起，一例为疫苗诱发血小板减少性血栓造成。
Adverse Events Following Immunization (AEFIs) for COVID-19 in Ontario: December 13, 2020 to September 11, 2021
Summary of AEFI reports in Ontario
An AEFI report refers to a report received by the PHU, which pertains to one individual vaccine recipient who reported at least one adverse event after receiving the COVID-19 vaccine (i.e., temporally associated with the vaccine).
See Table 1 for a summary of all AEFI reports received to date in Ontario. Of the total number of AEFI reports, 68.5% are reported to be associated with the first dose of COVID-19 vaccination using the information from CCM whereas 21.4% are reported to be associated with the second dose. There are two reports associated with the third dose. The remaining reports have unknown or missing dose number in CCM.
Table 1. Summary of all AEFI reports received to date by COVID-19 vaccine: Ontario, December 13, 2020 to September 11, 2021
Note: Five AEFI reports did not specify vaccine product received. Data corrections or updates can result in AEFI reports being removed and/or updated from past reports and may result in counts differing from past publicly reported AEFIs.
MYOCARDITIS/PERICARDITIS
There have been international reports, including from the United States and Israel, of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) following vaccination with COVID-19 mRNA vaccines.11,12 Information to date indicates that these events occur more commonly after the second dose, within the week following vaccination (typically within 4-5 days), mainly in adolescents/young adults and more often in males than females.
PHAC and Health Canada are closely monitoring these events in passive and active Canadian vaccine safety surveillance systems.
As of September 11, 2021, there have been 369 reports of myocarditis or pericarditis following receipt of COVID-19 mRNA vaccines in Ontario. These reports have been identified through case-level review of all reported AEFIs. Of these, 100 (27.10%) were diagnosed with myocarditis and 162 (43.9%) were diagnosed with pericarditis. The remaining 107 (29.0%) were diagnosed with perimyocarditis (n=18), myopericarditis (n=86) and myocarditis/pericarditis (n=3). The 100 reports of myocarditis have been assessed using the Brighton Collaboration case definition for myocarditis; 95 reports met Brighton levels of diagnostic certainty 1, 2 or 3 (95.1%), three reports had insufficient evidence to meet level 1, 2 or 3 of the case definition (3.0%) and one report did not meet the Brighton Collaboration case definition for myocarditis (1.0%). 14 One report could not be assessed due to lack of information. Of the 162 reports of pericarditis assessed using the Brighton Collaboration case definition for pericarditis, 88 reports met Brighton levels of diagnostic certainty 1, 2 or 3 (54.3%), 54 reports had insufficient evidence to meet level 1, 2 or 3 of the case definition (33.3%), and 19 reports did not meet the Brighton Collaboration case definition for pericarditis (11.7%). 14One report could not be assessed due to lack of information. See Table 3 for further characteristics of myocarditis/pericarditis reports. The remaining 107 reports were assessed against both Brighton Collaboration case definition for myocarditis and pericarditis to see if they meet either one of two definitions; of these, 97 (90.7%) met Brighton levels of diagnostic certainty 1, 2 or 3 for either myocarditis or pericarditis.
Of the 369 reports of myocarditis or pericarditis, 208 (56.4%) reports had a hospital admission with some variation by age group. Among the 180 reports where both the date of admission and discharge was available for review, the median length of stay was two days.
Based on 369 reports of myocarditis or pericarditis, the overall crude reporting rate is 18.5 per million doses of mRNA vaccines administered. The highest reporting rates were observed in younger age groups (12-17 and 18-24 years) and among males. The highest reporting rate was observed for males aged 18- 24 years of age following dose 2, at 168.7 events per million doses administered. Table A3 in Appendix A presents the reporting rate of myocarditis or pericarditis by age group, gender and dose number. The reporting rates are calculated by including all reports of myocarditis or pericarditis identified through case-level review, regardless of whether they meet the Brighton Collaboration case definition for myocarditis or pericarditis.
Additionally, there are 70 reports classified as ‘persons under investigation’ as public health units are still collecting additional information on the AEFI report. Ontario is continuing to monitor these events in collaboration with its partners and weekly updates can be found within this report and on the PHAC website. Please see PHO’s At A Glance: Myocarditis and Pericarditis Following COVID-19 mRNA Vaccines for more information on this topic.15Additional in-depth analysis of myocarditis/pericarditis reports in Ontario is available on Myocarditis and Pericarditis Following Vaccination with COVID-19 mRNA Vaccines in Ontario: December 13, 2020 to August 7, 2021.
Note: Thirteen reports with unknown time to onset and 13 reports with time to onset of greater than 42 days have been excluded from the calculation of median time to onset and range.
Serious AEFIs
In Ontario, AEFIs that meet the serious definition are events that required hospital admission and reports of death (see the technical notes for a full definition). There were 673 AEFI reports classified as serious, representing 5.4% of all AEFI reports and a serious AEFI reporting rate of 3.2 per 100,000 doses administered for all vaccine products combined. As a comparison, the proportion of AEFIs defined as serious for all vaccines administered in Ontario ranged from 2.8% and 5.0% between 2012 and 2018.17 The serious reporting rate was 2.4 and 3.9 per 100,000 doses administered for the Pfizer-BioNTech vaccine and the Moderna vaccine, respectively. The serious reporting rate for the AstraZeneca/COVISHIELD vaccine was 9.8 per 100,000 doses administered.
AEFI REPORTS REQUIRING HOSPITALIZATION
Of the 673 reports meeting the serious definition, 667 reports had a hospital admission related to the reported events. Table 4 summarizes the outcome of the 667 reports at the time of reporting and the event that was the prominent reason for hospitalization.
Table 4. Summary of outcomes and events for AEFI reports requiring hospitalization: Ontario, December 13, 2020 to September 11, 2021
Note: * an outcome reported as “residual effects” is defined as residual disability or sequelae related to the reported event. Due to the relatively short follow-up time for AEFIs reported in CCM, it is uncertain whether these residual effects will resolve, but had not yet resolved at the time of reporting.
AEFI REPORTS WITH FATAL OUTCOME
The remaining six serious AEFIs were reports of death following receipt of COVID-19 vaccine that met the provincial surveillance definition (i.e., other severe/unusual event) as follows:
Resident of a health-care institution with significant co-morbidities. The cause of death was not attributed to the vaccine.
Community dwelling senior with complex cardiovascular and renal conditions, wherein the AEFI may have contributed to but was not the underlying cause of death.
Community dwelling senior with multiple comorbidities including heart disease and an autoimmune disorder. The cause of death was not attributed to the vaccine.
An individual with VITT with death recorded in CCM (described above under Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) and Thrombosis with Thrombocytopenia Syndrome (TTS)).
Individual with hypertension, wherein the cause of death was not clearly attributed to vaccine.
Community dwelling senior with a complex cardiovascular history. The AEFI may have contributed to but was not the underlying cause of death.
Reports of death temporally associated with receipt of vaccine
In Ontario, all deaths temporally associated with receipt of vaccines that have been reported to public health units are thoroughly investigated and reported to PHO. As of September 11, 2021, there are 34 reports of deaths temporally associated with receipt of COVID-19 vaccine that are currently classified as ‘persons under investigation’ as they do not currently meet the provincial surveillance definition. These investigations are ongoing and additional information including a cause of death (e.g., autopsy or Coroner’s report) is expected. Preliminary information suggests that these events occurred in individuals with multiple co-morbidities which may be related to the cause of death. Six of the 34 reports are in long-term care home (LTCH)/retirement home residents. There has been no association with vaccine identified at this time. Reports of death that meet the provincial case definition are events temporally associated with vaccine that have not been clearly attributed to other causes; these reports should not be interpreted as causally related with vaccine.
During the first few months of the COVID-19 vaccination campaign, LTCH/retirement home residents have been a focus for vaccination efforts. In this population, it was expected that deaths may occur close to the time of vaccination and require further evaluation to determine the cause of death. After reviewing reports of deaths of very frail elderly individuals vaccinated with Pfizer-BioNTech COVID-19 vaccine, the Global Advisory Committee on Vaccine Safety (GACVC) COVID-19 Vaccine Safety subcommittee concluded that “the current reports do not suggest any unexpected or untoward increase in fatalities in frail, elderly individuals or any unusual characteristics of adverse events following administration of Pfizer-BioNTech COVID-19 vaccine”.18 The Centres for Disease Control (CDC) also presented a similar assessment of their analysis at the January 27, 2021 meeting of the Advisory Committee on Immunization Practices (ACIP) in the United States that mortality in LTCH residents is high and substantial numbers of deaths in this population are expected, unrelated to vaccination.19 PHO continues to conduct continuous monitoring of the safety of COVID-19 vaccines in collaboration with its partners, including individual case review of all serious AEFIs including reports of death temporally association with receipt of vaccine, daily analysis of surveillance data for vaccine safety signals and weekly reporting on the PHO website and to the Public Health Agency of Canada.
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