12月13日至5月8日,共86例严重不良反应,10万分之1.4。
阿斯利康疫苗共发生11例血小板减少症(TTS),1.7 / 10万 = 1 / 6万,其中8例由疫苗诱导的免疫性血小板减少症(VITT),1.2 / 10万 = 1 / 8万。截止到上次报告,(一周前,5月1日)TTS仅3例,全部为50岁以上的男性。
共有10人死亡暂时可能与疫苗相关,其中5人是老人院成员。
Highlights
There are a total of 2,684 AEFI reports received following 6,147,144 doses of COVID-19 vaccines administered in Ontario to date with a reporting rate of 43.7 per 100,000 doses administered
This represents an increase of 404 AEFI reports compared to previous week
Of the total 2,684 AEFI reports received to date:
2,598 AEFI reports are non-serious (96.8% of total AEFI reports)
86 AEFI reports meet the serious definition (3.2% of total AEFI reports)
The most commonly reported adverse events are allergic skin reactions and pain/redness/swelling at the injection site, reported in 26.6% and 25.7% of the total AEFI reports respectively
113 reports of events managed as anaphylaxis are reported, in which 11 reports also meet the serious definition (see Events Managed As Anaphylaxis for description of events)
60 reports include a COVID-19 vaccine-specific adverse event of special interest, in which 25 reports also meet the serious definition (see Adverse events of special interest for description of events)
Eleven reports of thrombosis with thrombocytopenia syndrome (TTS) after receipt of COVISHIELD/AstraZeneca vaccine, of which eight are vaccine-induced immune thrombotic thrombocytopenia (VITT)
Note: AEFI reports are assessed based on date of vaccine administration. The administration week ranges from week 51 (Dec 13 to 19, 2020) to week 18 (May 2 to 8, 2021). The number of AEFI reports for the recent reporting weeks are subject to reporting delays and/or delayed data entry (i.e., reports are likely to be still under investigation and yet to be reported as a confirmed AEFI report). 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.
Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) and Thrombosis with Thrombocytopenia Syndrome (TTS)
Thrombosis with Thrombocytopenia Syndrome (TTS) is a condition characterized by the presence of acute venous or arterial thrombosis with new onset thrombocytopenia (low levels of platelets), and no known recent exposure to heparin.7 A case finding definition proposed by the Brighton Collaboration is being used to support the investigation of this new clinical syndrome by identifying individuals who present with TTS following COVID-19 vaccination.7 Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT) refers to the clinical syndrome of TTS, in addition to laboratory tests that confirm platelet activation (i.e., anti-platelet 4 antibodies). VITT has been reported following immunization with COVID-19 adenoviral vector vaccines, including COVISHIELD/AstraZeneca vaccine.
The rate of VITT is currently estimated to be approximately 1 per 100,000 persons vaccinated with COVISHIELD/AstraZeneca vaccine, although information in this area is rapidly evolving.
To date, there have been
11 reports of TTS following receipt of COVISHIELD/AstraZeneca vaccine in Ontario; of these,
eight are VITT. The two most recent events had a vaccination date of April 23, 2021. The following reporting rates are based on the number of doses of COVISHIELD/AstraZeneca vaccines administered in Ontario as of April 24, 2021 (643,714 doses) as the denominator, which accounts for the lag period from vaccination to subsequent symptom onset, clinical recognition and reporting to the vaccine safety surveillance system. The reporting rate of
TTS based on 11 reports is 1.7 per 100,000 (approximately 1 in 60,000) doses administered. The reporting rate of
VITT (as a subtype of TTS) based on eight reports is 1.2 per 100,000 (approximately 1 in 80,000) doses administered. Reporting rate calculations are subject to changes over time including additional events that are diagnosed and reported to the vaccine safety surveillance system, as well as increases in doses administered over time.
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
86 AEFI reports classified as serious, representing 3.2% of all AEFI reports and a serious AEFI reporting rate of 1.4 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 2018.9 The serious reporting rate was
1.2 and 1.5 per 100,000 doses administered for the Pfizer-BioNTech vaccine and the Moderna vaccine, respectively. The serious reporting rates for the
COVISHIELD and AstraZeneca vaccines were 6.4 and 1.2 per 100,000 doses administered, respectively.
AEFI Reports Requiring Hospitalization
Eighty-three clients of the 86 serious reports had a hospital admission related to the reported events. Of the 83 clients, 30 had recovered at the time of reporting, 38 were not yet recovered when the investigation was completed, but likely to recover, and nine had an unknown outcome at the time of reporting. Six reports had an outcome reported as “residual effects”, which 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. Adverse Events Following Immunization (AEFIs) for COVID-19 in Ontario 8 When a serious report contained multiple adverse events, one event that was the pro
When a serious report contained multiple adverse events, one event that was the prominent reason for reporting was chosen to describe the serious report. Of the 83 reports of hospitalizations, 19 reported an AESI, 22 reported a medically important event, and six reported both a medically important event and an AESI (described in the AESI section and the medically important events section). The remaining 36 reports were:
24 reports of other severe or unusual events
four reports of severe vomiting/diarrhea
three reports of convulsion/seizure
two reports of anaesthesia/paraesthesia
one report of syncope (fainting) with injury
one report of arthritis/arthralgia
one report of paralysis
AEFI Reports with Fatal Outcome
The remaining
three serious AEFIs were reports of death following receipt of COVID-19 vaccine that met the provincial surveillance definition (i.e., other severe/unusual event). One report of death occurred in a resident of a health-care institution with significant co-morbidities. The cause of death was not attributed to the vaccine. The second report of death occurred in a community dwelling senior with complex cardiovascular and renal conditions, wherein the AEFI may have contributed to but was not the underlying cause of death. The third report of death occurred in a community dwelling senior with multiple comorbidities including heart disease and an autoimmune disorder. The cause of death was not attributed to the vaccine.
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 May 8, 2021, there are
ten 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.
Five of the ten 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 Adverse Events Following Immunization (AEFIs) for COVID-19 in Ontario 9 in fatalities in frail, elderly individuals or any unusual characteristics of adverse events following administration of Pfizer-BioNTech COVID-19 vaccine”.10 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.11 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.