Summary Background Multisystem inflammatory syndrome in children (MIS-C) is a hyperinflammatory condition associated with prior SARS-CoV-2 infection. In the US, MIS-C reporting is required after vaccination under COVID-19 vaccine emergency use authorizations. Our objective was to investigate reports of people aged 12 to 20 years with MIS-C after COVID-19 vaccination reported to passive surveillance systems or through medical disclosure to the Centers for Disease Control and Prevention ( CDC) Methods In this surveillance activity, we investigated potential cases of MIS-C following COVID-19 vaccination reported to CDC’s national MIS-C surveillance system, the Vaccine Adverse Event Reporting System (co-managed by CDC and US Food and Drug Administration), and CDC Clinical Immunization Safety Assessment Project. erpos against the nucleocapsid indicate a previous SARS-CoV-2 infection, antibodies against the spike protein indicate a past or recent infection or vaccination against COVID-19. We describe the demographic and clinical characteristics of the cases, stratified by laboratory evidence of SARS-CoV-2 infection. To calculate the MIS-C notification rate, we divide the count of all people meeting the MIS-C case definition, and those without evidence of SARS-CoV-2 infection, by the number of people out of 12 20 years in the group. USA who received one or more doses of the COVID-19 vaccine through August 31, 2021, obtained from CDC national vaccine surveillance data. Results Using surveillance results from December 14, 2020 to August 31, 2021, we identified 21 individuals with MIS-C after COVID-19 vaccination. Of these 21 individuals, the median age was 16 years (range 12-20); 13 (62%) were men and eight (38%) were women. All 21 were hospitalized: 12 (57%) were admitted to an intensive care unit and all were discharged. 15 (71%) of 21 people had laboratory evidence of past or recent SARS-CoV-2 infection, and six (29%) did not. As of August 31, 2021, 21,335,331 people ages 12 to 20 had received one or more doses of a COVID-19 vaccine, making the overall reporting rate of MIS-C after vaccination 1.0 cases per million people receiving one or more doses in this age group. The notification rate only in those without evidence of SARS-CoV-2 infection was 0.3 cases per million vaccinated people. Interpretation Here, we describe a small number of people with MIS-C who received one or more doses of a COVID-19 vaccine before illness onset; The contribution of vaccination to these diseases is unknown. Our findings suggest that MIS-C after COVID-19 vaccination is rare. Continued reporting of potential cases and surveillance for MIS-C disease following COVID-19 vaccination is warranted. |
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Highlights
- Researchers report surveillance data recording cases of multisystem inflammatory syndrome in children (MIS-C) among people ages 12 to 20 who received at least one dose of a COVID-19 vaccine during the first nine months into the US COVID-19 vaccination program.
- Over the nine-month period, more than 21 million children and adolescents in this age group received at least one dose of the COVID-19 vaccine, and a total of 21 cases of MIS-C were identified, suggesting that MIS -C occurred in one per million vaccinated people. , which is substantially lower than previous estimates of 200 cases per million in unvaccinated people infected with SARS-CoV-2.
- Six identified cases of MIS-C had no evidence of SARS-CoV-2 infection, suggesting that the rate of cases without evidence of SARS-CoV-2 infection was 0.3 cases per million people vaccinated in this age group. The authors emphasize that they cannot determine whether the vaccine contributed to these rare cases or if there were other reasons for the illness, such as other unrecognized underlying inflammatory conditions.
Reported cases of multisystem inflammatory syndrome (MIS-C) in children and adolescents who had received at least one dose of the COVID-19 vaccine were rare (estimated at one case per million vaccinated people in this age group). The notification rate of cases without evidence of SARS-CoV-2 infection was 0.3 cases per million vaccinated people in this age group, according to an observational study published in the journal The Lancet Child & Adolescent Health.
Although no direct comparator is available, this research found that the rate of MIS-C cases in vaccinated children and adolescents aged 12 to 20 years in the US -CoV-2 during April to June 2020.
Dr. Anna R. Yousaf of the US Centers for Disease Control and Prevention (CDC) says: “As part of the comprehensive effort to monitor COVID-19 vaccine safety in the United States , the CDC has been closely monitoring cases of MIS-C in vaccinated children.
Our results suggest that cases of MIS-C after COVID-19 vaccination are rare and that the likelihood of developing MIS-C is much higher in unvaccinated children who contract COVID-19.
“COVID-19 vaccination is recommended for everyone age 5 and older in the United States for the prevention of COVID-19.”
MIS-C, also known as pediatric multisystem inflammatory syndrome (PIM-TS), is a rare condition associated with SARS-CoV-2 infection that was first recognized in April 2020. MIS-C is believed to be a immune exaggerated reaction that occurs approximately two to six weeks after SARS-CoV-2 infection in children and adolescents.
Symptoms include fever, rash, red eyes, and gastrointestinal symptoms (e.g., diarrhea, stomach pain, nausea) and may lead to multiple organ failure. In the US, reporting of possible MIS-C cases after vaccination is required under emergency use authorizations of the COVID-19 vaccine.
US Centers for Disease Control and Prevention Case Definition for Multisystem Inflammatory Syndrome in Children
Current or recent* SARS-CoV-2 positive RT-PCR, antigen or serological test; or exposure to a suspected or confirmed case of COVID-19 within 4 weeks before symptom onset † *For this research, this criterion could be met with any type of nucleic acid amplification test. †The exposure criterion was not used in this investigation. |
This study investigated cases of MIS-C in children and adolescents aged 12 to 20 years reported during the first nine months of the COVID-19 vaccination rollout in the US (December 14, 2020 to August 31 2021).
A team of medical specialists and epidemiologists examined 47 reports of possible MIS-C illness occurring in a person aged 12 to 20 years at any time after a dose of COVID-19 vaccine. Of these 47 reports, 21 fit the CDC MIS-C criteria. These were separated into those with and without evidence of past or recent SARS-CoV-2 infection from laboratory testing.
They calculated case notification rates using CDC national vaccine surveillance data on the number of people ages 12 to 20 in the U.S. who received one or more doses of the COVID-19 vaccine.
Of the 21 MIS-C cases, 15 had evidence of past or recent SARS-CoV-2 infection, while six did not. More than 21 million children and adolescents aged 12 to 20 years had received one or more doses of a COVID-19 vaccine, representing one reported case per million vaccinated people in this age group. The MIS-C notification rate for those without evidence of SARS-CoV-2 infection was 0.3 cases per million vaccinated people.
The authors emphasize that they cannot determine whether vaccination contributed to MIS-C disease in these rare cases. Since MIS-C was first identified during the pandemic, there is no baseline rate of inflammatory diseases in children and adolescents with an unidentified cause to estimate a baseline number of cases expected to occur in any nine-year period. months, regardless of COVID-19 infection or vaccination. . It is possible that some of the identified cases had other unrecognized inflammatory conditions that occurred coincidentally after vaccination.
Of the 15 people with prior SARS-CoV-2 infection, three were diagnosed with MIS-C outside the typical two to six week period (14─42 days) when subsequent MIS-C disease is most likely to occur. These three had MIS-C onset 105 days, 191 days, and 238 days after their positive SARS-CoV-2 test.
All 21 people were hospitalized, 12 were admitted to an intensive care unit and all were discharged. The median age was 16 years; 13 were men and eight were women.
All people with MIS-C in the study received the Pfizer-BioNTech COVID-19 vaccine (BNT162b2), which was the only COVID-19 vaccine authorized in the US for use in children under 18 years of age during the study period. study.
11 people received one dose and 10 received two doses of the vaccine before the onset of MIS-C illness. The median time from dose to hospitalization was eight days for those who had received one vaccine dose and five days for those who had received two.
Dr. Yousaf continues: “As with the COVID-19 disease, doctors and researchers are still learning about MIS-C. “Our research highlights the challenges in diagnosing MIS-C, the importance of considering alternative diagnoses, and the need to monitor MIS-C disease.” [2]
The authors point out some additional limitations of their study. It is possible that some of the identified cases of MIS-C had another inflammatory disease with similar symptoms, as there is no definitive test to diagnose MIS-C. Because laboratory testing for COVID-19, including antibody tests, is imperfect, some cases may have been misclassified.
Children often experience mild or asymptomatic infections, and milder infections are less likely to generate antibodies, which can cause previous infections to go undetected. It is also possible that not all cases of MIS-C after vaccination have been reported in the surveillance system, which could lead to underreporting of the number of cases.
In a linked comment, lead author Dr Mary Beth Son, from Boston Children’s Hospital, US (who was not involved in the study), says: “Their findings overall are quite reassuring. Reports of MIS-C after COVID-19 vaccination occurred in only 1 per million people ages 12 to 20 who received one or more doses of a COVID-19 vaccine, and 15 (71%) of 21 people with MIS-C had laboratory testing. evidence of a history of SARS-CoV-2 infection, casting doubt on attribution.
This timely report is of particular interest to healthcare providers, scientists, and policymakers, given the widespread and ongoing transmission of the omicron variant (B.1.1.529). As the pandemic continues to challenge our global community and intense scrutiny of COVID-19 vaccines persists, Yousaf and colleagues’ report is a welcome addition to the growing literature supporting the safety and effectiveness of COVID-19 vaccination. "SARS CoV-2."
Implications of all available evidence During the first 9 months of the COVID-19 vaccination program in the US, more than 21 million people ages 12 to 20 received one or more doses of a COVID-19 vaccine as of March 31. August 2021. This case series describes MIS-C with onset after vaccination in 21 individuals, most of whom also had evidence of SARS-CoV-2 infection. Although our surveillance has limitations, our findings suggest that the MIS-C identified in this report after COVID-19 vaccination is rare. When evaluating individuals with a clinical presentation consistent with MIS-C following COVID-19 vaccination, it is important to consider alternative diagnoses and determine whether prior SARS-CoV-2 infection has occurred. In this sense, testing for antinucleocapsid antibodies could be useful, ideally from a serum sample obtained before the administration of intravenous immunoglobulin. Continued surveillance for MIS-C disease following COVID-19 vaccination is warranted, especially as pediatric COVID-19 vaccination is authorized and recommended for younger children who comprise the largest proportion of MIS-C cases. after SARS-Cov-2 infection. |
