Safety and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in inadvertently vaccinated healthy children

Abstract

Twenty-seven children aged seven months to 5 years were inadvertently vaccinated with a COVID-19 vaccine, the CoronaVac (Sinovac, China), an inactivated SARS-CoV-2 vaccine, in two different cities of Sao Paulo State, Brazil. After the event, these children were monitored by local pediatricians and serum samples were collected at the first visit and 30 days after vaccination and tested for SARS-CoV-2 S1 serology with Ortho total IgG anti-S1 protein and Cpass, an ACE2 receptor binding domain inhibition assay. Only one child had a mild symptom after vaccination, with no other adverse events documented up to the 30 days follow-up. Of 27 children tested 3-9 days after vaccination, 5 (19%) had positive serology suggesting a previous natural SARS-CoV-2 infection, with all 19 tested on day 30 after vaccination and presenting with positive tests, with an increment of antibody titers in those initially positive. A low Cpass binding inhibition was observed in the first collection in 11 seronegative cases, with high titers among those anti-S1 positive. All children showed an important increase in antibody titers on day 30. The event allowed the documentation of a robust serological response to one dose of CoronaVac in this small population of young children, with no major adverse effects. Although it was an unfortunate accident, this event may contribute with future vaccine strategies in this age group. The data suggest that CoronaVac is safe and immunogenic for children.

Vaccination against COVID‐19 and potential protective effects on seizure recurrence in children with epilepsy: A cross‐sectional survey

“…In China, the current lower age limit for inactivated COVID‐19 vaccination is >3 years. The efficacy and safety of the inactivated CoronaVac vaccine has also been confirmed in this population in other countries beyond China 12,13 . Despite the demonstrated safety, immunogenicity, and effectiveness of the BNT162b2 COVID‐19 vaccine in children aged 6 months to 4 years, 14 there is a need for further exploration regarding the possibility of extending the lower age limit for inactivated vaccines and conducting large‐scale comparative studies involving different vaccine formulations.…”

“…The efficacy and safety of the inactivated CoronaVac vaccine has also been confirmed in this population in other countries beyond China. 12,13 Despite the demonstrated safety, immunogenicity, and effectiveness of the BNT162b2 COVID-19 vaccine in children aged 6 months to 4 years, 14 there is a need for further exploration regarding the possibility of extending the lower age limit for inactivated vaccines and conducting large-scale comparative studies involving different vaccine formulations. While vaccinations are not implicated in epileptic encephalopathies such as DS, they may act as non-specific triggers of seizures in individuals with underlying structural or genetic etiologies.…”

A systematic review of current status and challenges of vaccinating children against SARS-CoV-2

“…1 B) [48] , [140] . Following, the non-replicating viral vector and inactivated vaccines were successively authorized by WHO for children over 12 years old [106] , [141] , [142] . Table 1 lists the status and immune efficacy of authorized COVID-19 vaccines for children, including mRNA vaccines (Pfizer-BioNTech, Moderna), non-replicating viral vector (Oxford/AstraZeneca, Ad26COVS1) and inactivated vaccines (Sinopharm, Sinovac).…”

“…COV 2. SOther names: Janssen (Johnson & Johnson); Ad26COVS1 *WHO EUL; *CRS EUR *ART Endorsed 12/03/2021 106 Pause 66.9% (prevention of severe COVID-19); 76.7% (severe-critical COVID-19) for adult (USA, Brazil, and South Africa) Age: 18 years and older Intervals: 2 months [154] , [155] , [156] , [157] , [158] Inactivated vaccine BBIBP-CorV Other names: Sinopharm (Beijing); Covilo *WHO EUL; *CRS EUR *ART Endorsed 05/07/2021 88 3–17 (Phase 3 clinical trial) 100% (neutralization activity) (China) Age: 3 years and older Intervals: at least 28 days (two or three doses) [113] , [142] , [159] , [160] CoronaVac Other names: Sinovac *WHO EUL; *CRS EUR *ART Endorsed 06/01/2021 52 6 months and more (Phase 3 clinical trial) 100% (neutralization antibody activity) 100% (immunogenicity) (China) Age: 3 years and older Intervals: 28 days (second dose) 6 months (third dose) [106] , [141] , [161] *WHO EUL: World Health Organization Emergency Use Listing *CRS EUR: Caribbean Regulatory System Emergency Use Recommendation *ART: Africa Regulatory Taskforce (ART) Endorsed …”

Safety and efficacy of COVID-19 Vaccines in special populations

“…61 Rare adverse events such as serious cutaneous and allergic reactions, nephrotic syndrome, optic neuritis and subacute thyroiditis, bell's palsy, bronchial asthma was also reported. [64][65][66][67][68][69][70][71][72][73] In Brazil, good efficacy of this vaccine was observed in the elderly. After two doses of the vaccine, better protection ratios were obtained, with an attributable protection ratio of 99.2%.…”