Impact of a delayed second dose of mRNA vaccine (BNT162b2) and inactivated SARS-CoV-2 vaccine (CoronaVac) on risks of all-cause mortality, emergency department visit, and unscheduled hospitalization

A modeling-based approach to optimize COVID-19 vaccine dosing schedules for improved protection

While the development of different vaccines slowed the dissemination of SARS-CoV-2, the occurrence of breakthrough infections has continued to fuel the COVID-19 pandemic. To secure at least partial protection in the majority of the population through 1 dose of a COVID-19 vaccine, delayed administration of boosters has been implemented in many countries. However, waning immunity and emergence of new variants of SARS-CoV-2 suggest that such measures may induce breakthrough infections due to intermittent lapses in protection. Optimizing vaccine dosing schedules to ensure prolonged continuity in protection could thus help control the pandemic. We developed a mechanistic model of immune response to vaccines as an in silico tool for dosing schedule optimization. The model was calibrated with clinical data sets of acquired immunity to COVID-19 mRNA vaccines in healthy and immunocompromised participants and showed robust validation by accurately predicting neutralizing antibody kinetics in response to multiple doses of COVID-19 mRNA vaccines. Importantly, by estimating population vulnerability to breakthrough infections, we predicted tailored vaccination dosing schedules to minimize breakthrough infections, especially for immunocompromised individuals. We identified that the optimal vaccination schedules vary from CDC-recommended dosing, suggesting that the model is a valuable tool to optimize vaccine efficacy outcomes during future outbreaks.

Incidence of diabetes following COVID-19 vaccination and SARS-CoV-2 infection in Hong Kong: A population-based cohort study

BACKGROUND

The risk of incident diabetes following Coronavirus Disease 2019 (COVID-19) vaccination remains to be elucidated. Also, it is unclear whether the risk of incident diabetes after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is modified by vaccination status or differs by SARS-CoV-2 variants. We evaluated the incidence of diabetes following mRNA (BNT162b2), inactivated (CoronaVac) COVID-19 vaccines, and after SARS-CoV-2 infection.

METHODS AND FINDINGS

In this population-based cohort study, individuals without known diabetes were identified from an electronic health database in Hong Kong. The first cohort included people who received ≥1 dose of COVID-19 vaccine and those who did not receive any COVID-19 vaccines up to September 2021. The second cohort consisted of confirmed COVID-19 patients and people who were never infected up to March 2022. Both cohorts were followed until August 15, 2022. A total of 325,715 COVID-19 vaccine recipients (CoronaVac: 167,337; BNT162b2: 158,378) and 145,199 COVID-19 patients were 1:1 matched to their respective controls using propensity score for various baseline characteristics. We also adjusted for previous SARS-CoV-2 infection when estimating the conditional probability of receiving vaccinations, and vaccination status when estimating the conditional probability of contracting SARS-CoV-2 infection. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident diabetes were estimated using Cox regression models. In the first cohort, we identified 5,760 and 4,411 diabetes cases after receiving CoronaVac and BNT162b2 vaccines, respectively. Upon a median follow-up of 384 to 386 days, there was no evidence of increased risks of incident diabetes following CoronaVac or BNT162b2 vaccination (CoronaVac: 9.08 versus 9.10 per 100,000 person-days, HR = 0.998 [95% CI 0.962 to 1.035]; BNT162b2: 7.41 versus 8.58, HR = 0.862 [0.828 to 0.897]), regardless of diabetes type. In the second cohort, we observed 2,109 cases of diabetes following SARS-CoV-2 infection. Upon a median follow-up of 164 days, SARS-CoV-2 infection was associated with significantly higher risk of incident diabetes (9.04 versus 7.38, HR = 1.225 [1.150 to 1.305])-mainly type 2 diabetes-regardless of predominant circulating variants, albeit lower with Omicron variants (p for interaction = 0.009). The number needed to harm at 6 months was 406 for 1 additional diabetes case. Subgroup analysis revealed no evidence of increased risk of incident diabetes among fully vaccinated COVID-19 survivors. Main limitations of our study included possible misclassification bias as type 1 diabetes was identified through diagnostic coding and possible residual confounders due to its observational nature.

CONCLUSIONS

There was no evidence of increased risks of incident diabetes following COVID-19 vaccination. The risk of incident diabetes increased following SARS-CoV-2 infection, mainly type 2 diabetes. The excess risk was lower, but still statistically significant, for Omicron variants. Fully vaccinated individuals might be protected from risks of incident diabetes following SARS-CoV-2 infection.

Risk of Adverse Events and Delirium After COVID-19 Vaccination in Patients Living With Dementia

OBJECTIVES

The aim of this study was to compare incidences of adverse events of special interest (AESI) and delirium in 3 cohorts: after COVID-19 vaccination, prepandemic, and SARS-CoV-2 polymerase chain reaction (PCR) test positive.

DESIGN

This is a population-based cohort study using electronic medical records linked with vaccination records in Hong Kong.

SETTING AND PARTICIPANTS

A total of 17,449 older people with dementia received at least 1 dose of CoronaVac (n = 14,719) or BNT162b2 (n = 2730) between February 23, 2021, and March 31, 2022. Moreover, 43,396 prepandemic and 3592 SARS-CoV-2 test positive patients were also included in this study.

METHODS

The incidences of AESI and delirium up to 28 days after vaccination in the vaccinated dementia cohort were compared with the prepandemic and SARS-CoV-2 test positive dementia cohorts by calculating incidence rate ratios (IRRs). Patients who received multiple doses were followed up separately for each dose, up to the third dose.

RESULTS

We did not detect an increased risk of delirium and most AESI following vaccination compared to the prepandemic period and those tested positive for SARS-CoV-2. No AESI group nor delirium incidence exceeded 10 per 1000 person-days in vaccinated individuals.

CONCLUSIONS AND IMPLICATIONS

The findings provide evidence for the safe use of COVID-19 vaccines in older patients with dementia. In the short run, benefit appears to outweigh the harm due to vaccine; however, longer follow-up should be continued to identify remote adverse events.

Effectiveness of BNT162b2 after extending the primary series dosing interval in children and adolescents aged 5-17

Extended intervals between the first and second doses of mRNA Covid-19 vaccines may reduce the risk of myocarditis in children and adolescents. However, vaccine effectiveness after this extension remains unclear. To examine this potential variable effectiveness, we conducted a population-based nested case-control study of children and adolescents aged 5-17 years who had received two doses of BNT162b2 in Hong Kong. From January 1 to August 15, 2022, 5396 Covid-19 cases and 202 Covid-19 related hospitalizations were identified and matched with 21,577 and 808 controls, respectively. For vaccine recipients with extended intervals [≥28 days, adjusted odds ratio 0.718, 95% Confidence Interval: 0.619, 0.833] there was a 29.2%-reduced risk of Covid-19 infection compared to those with regular intervals (21-27 days). If the threshold was set at eight weeks, the risk reduction was estimated at 43.5% (aOR 0.565, 95% CI: 0.456, 0.700). In conclusion, longer dosing intervals for children and adolescents should be considered.

A 1-year analysis of adverse events following COVID-19 vaccination in Lebanon: a retrospective study

BACKGROUND

Since the deployment of Coronavirus Disease 2019 (COVID-19) vaccines, skepticism about the safety, incidence, and severity of Adverse Events Following Immunization (AEFI) was a concern. The study has two main objectives. First, to analyze AEFIs following COVID-19 vaccines (Pfizer-BioNTech, AstraZeneca, Sputnik, and Sinopharm) during the vaccination campaign in Lebanon and correlate them with age and gender. Second, to correlate Pfizer-BioNTech and AstraZeneca vaccines' AEFI with the dose administered.

METHODS

A retrospective study was carried out between February 14th, 2021, and February 14th, 2022. AEFI case reports received to the Lebanese Pharmacovigilance (PV) Program were cleaned, validated, and analyzed using SPSS software.

RESULTS

A total of 6808 AEFI case reports were received to the Lebanese PV Program during the period of this study. Case reports were mostly received from females (60.7%) and from vaccine recipients aged 18-44 years. As for the vaccine type, AEFIs occurred more frequently with the AstraZeneca vaccine compared to the Pfizer-BioNTech vaccine. The latter had AEFIs mainly following dose 2, whereas AEFIs with the AstraZeneca vaccine were more frequently reported after dose 1, with general body pain being the most reported systemic AEFI with PZ (34.6%), while fatigue was the most reported AEFI with AZ vaccine (56.5%).

CONCLUSIONS

The AEFI reported with COVID-19 vaccines in Lebanon were aligned with those reported worldwide. The incidence of rare serious AEFIs should not discourage the public from getting vaccinated. Further studies are needed to evaluate their long-term potential risk.

A modeling-based approach to optimize COVID-19 vaccine dosing schedules for improved protection

While the development of different vaccines has slowed the dissemination of SARS-CoV-2, the occurrence of breakthrough infections continues to fuel the pandemic. As a strategy to secure at least partial protection, with a single dose of a given COVID-19 vaccine to maximum possible fraction of the population, delayed administration of subsequent doses (or boosters) has been implemented in many countries. However, waning immunity and emergence of new variants of SARS-CoV-2 suggest that such measures may jeopardize the attainment of herd immunity due to intermittent lapses in protection. Optimizing vaccine dosing schedules could thus make the difference between periodic occurrence of breakthrough infections or effective control of the pandemic. To this end, we have developed a mechanistic mathematical model of adaptive immune response to vaccines and demonstrated its applicability to COVID-19 mRNA vaccines as a proof-of-concept for future outbreaks. The model was thoroughly calibrated against multiple clinical datasets involving immune response to SARS-CoV-2 infection and mRNA vaccines in healthy and immunocompromised subjects (cancer patients undergoing therapy); the model showed robust clinical validation by accurately predicting neutralizing antibody kinetics, a correlate of vaccine-induced protection, in response to multiple doses of mRNA vaccines. Importantly, we estimated population vulnerability to breakthrough infections and predicted tailored vaccination dosing schedules to maximize protection and thus minimize breakthrough infections, based on the immune status of a sub-population. We have identified a critical waiting window for cancer patients (or, immunocompromised subjects) to allow recovery of the immune system (particularly CD4+ T-cells) for effective differentiation of B-cells to produce neutralizing antibodies and thus achieve optimal vaccine efficacy against variants of concern, especially between the first and second doses. Also, we have obtained optimized dosing schedules for subsequent doses in healthy and immunocompromised subjects, which vary from the CDC-recommended schedules, to minimize breakthrough infections. The developed modeling tool is based on generalized adaptive immune response to antigens and can thus be leveraged to guide vaccine dosing schedules during future outbreaks.

Risk of acute liver injury following the mRNA (BNT162b2) and inactivated (CoronaVac) COVID-19 vaccines

BACKGROUND & AIMS

Case reports of severe acute liver injury (ALI) following COVID-19 vaccination have recently been published. We evaluated the risks of ALI following COVID-19 vaccination (BNT162b2 or CoronaVac).

METHODS

We conducted a modified self-controlled case series analysis using the vaccination records in Hong Kong with data linkage to electronic medical records from a territory-wide healthcare database. Incidence rate ratios (IRRs) for ALI outcome in the 56-day period following first and second doses of COVID-19 vaccines in comparison to the non-exposure period were estimated and compared to the ALI risk in patients with SARS-CoV-2 infection.

RESULTS

Among 2,343,288 COVID-19 vaccine recipients who were at risk, 4,677 patients developed ALI for the first time between 23^rd February 2021 to 30^th September 2021. The number of ALI cases within 56 days after the first and second dose of vaccination were 307 and 521 (335 and 334 per 100,000 person-years) for BNT162b2, and 304 and 474 (358 and 403 per 100,000 person-years) for CoronaVac, respectively, compared to 32,997 ALI cases per 100,000 person-years among patients within 56 days of SARS-CoV-2 infection. Compared to the non-exposure period, no increased risk was observed in the 56-day risk period for first (IRR 0.800; 95% CI 0.680-0.942) and second (IRR 0.944; 95% CI 0.816-1.091) dose of BNT162b2, or first (IRR 0.689; 95% CI 0.588-0.807) and second (IRR 0.905; 95% CI 0.781-1.048) dose of CoronaVac. There were no severe or fatal cases of ALI following COVID-19 vaccination.

CONCLUSION

There was no evidence of an increased risk of ALI associated with BNT162b2 or CoronaVac vaccination. Based on all current available evidence from previous studies and our study, the benefit of mass vaccination far outweighs the ALI risk from vaccination.

LAY SUMMARY

There have been some recent reports that COVID-19 vaccination could be associated with acute liver injury. In our study, we found no evidence that COVID-19 vaccination increased the risk of acute liver injury, which was much more common after SARS-CoV-2 infection than after vaccination. Hence, our study provides further data indicating that the benefits of mass COVID-19 vaccination outweigh the potential risks.

Risk of thyroid dysfunction associated with mRNA and inactivated COVID-19 vaccines: a population-based study of 2.3 million vaccine recipients

BACKGROUND

In view of accumulating case reports of thyroid dysfunction following COVID-19 vaccination, we evaluated the risks of incident thyroid dysfunction following inactivated (CoronaVac) and mRNA (BNT162b2) COVID-19 vaccines using a population-based dataset.

METHODS

We identified people who received COVID-19 vaccination between 23 February and 30 September 2021 from a population-based electronic health database in Hong Kong, linked to vaccination records. Thyroid dysfunction encompassed anti-thyroid drug (ATD)/levothyroxine (LT4) initiation, biochemical picture of hyperthyroidism/hypothyroidism, incident Graves' disease (GD), and thyroiditis. A self-controlled case series design was used to estimate the incidence rate ratio (IRR) of thyroid dysfunction in a 56-day post-vaccination period compared to the baseline period (non-exposure period) using conditional Poisson regression.

RESULTS

A total of 2,288,239 people received at least one dose of COVID-19 vaccination (57.8% BNT162b2 recipients and 42.2% CoronaVac recipients). 94.3% of BNT162b2 recipients and 92.2% of CoronaVac recipients received the second dose. Following the first dose of COVID-19 vaccination, there was no increase in the risks of ATD initiation (BNT162b2: IRR 0.864, 95% CI 0.670-1.114; CoronaVac: IRR 0.707, 95% CI 0.549-0.912), LT4 initiation (BNT162b2: IRR 0.911, 95% CI 0.716-1.159; CoronaVac: IRR 0.778, 95% CI 0.618-0.981), biochemical picture of hyperthyroidism (BNT162b2: IRR 0.872, 95% CI 0.744-1.023; CoronaVac: IRR 0.830, 95% CI 0.713-0.967) or hypothyroidism (BNT162b2: IRR 1.002, 95% CI 0.838-1.199; CoronaVac: IRR 0.963, 95% CI 0.807-1.149), GD, and thyroiditis. Similarly, following the second dose of COVID-19 vaccination, there was no increase in the risks of ATD initiation (BNT162b2: IRR 0.972, 95% CI 0.770-1.227; CoronaVac: IRR 0.879, 95%CI 0.693-1.116), LT4 initiation (BNT162b2: IRR 1.019, 95% CI 0.833-1.246; CoronaVac: IRR 0.768, 95% CI 0.613-0.962), hyperthyroidism (BNT162b2: IRR 1.039, 95% CI 0.899-1.201; CoronaVac: IRR 0.911, 95% CI 0.786-1.055), hypothyroidism (BNT162b2: IRR 0.935, 95% CI 0.794-1.102; CoronaVac: IRR 0.945, 95% CI 0.799-1.119), GD, and thyroiditis. Age- and sex-specific subgroup and sensitivity analyses showed consistent neutral associations between thyroid dysfunction and both types of COVID-19 vaccines.

CONCLUSIONS

Our population-based study showed no evidence of vaccine-related increase in incident hyperthyroidism or hypothyroidism with both BNT162b2 and CoronaVac.

Messenger RNA Coronavirus Disease 2019 (COVID-19) Vaccination With BNT162b2 Increased Risk of Bell's Palsy: A Nested Case-Control and Self-Controlled Case Series Study

BACKGROUND

Observable symptoms of Bell's palsy following vaccinations arouse concern over the safety profiles of novel coronavirus disease 2019 (COVID-19) vaccines. However, there are only inconclusive findings on Bell's palsy following messenger (mRNA) COVID-19 vaccination. This study aims to update the previous analyses on the risk of Bell's palsy following mRNA (BNT162b2) COVID-19 vaccination.

METHODS

This study included cases aged ≥16 years with a new diagnosis of Bell's palsy within 28 days after BNT162b2 vaccinations from the population-based electronic health records in Hong Kong. Nested case-control and self-controlled case series (SCCS) analyses were used, where the association between Bell's palsy and BNT162b2 was evaluated using conditional logistic and Poisson regression, respectively.

RESULTS

Totally 54 individuals were newly diagnosed with Bell's palsy after BNT162b2 vaccinations. The incidence of Bell's palsy was 1.58 (95% confidence interval [CI], 1.19-2.07) per 100 000 doses administered. The nested case-control analysis showed significant association between BNT162b2 vaccinations and Bell's palsy (adjusted odds ratio [aOR], 1.543; 95% CI, 1.123-2.121), with up to 1.112 excess events per 100 000 people who received 2 doses of BNT162b2. An increased risk of Bell's palsy was observed during the first 14 days after the second dose of BNT162b2 in both nested case-control (aOR, 2.325; 95% CI, 1.414-3.821) and SCCS analysis (adjusted incidence rate ratio, 2.44; 95% CI, 1.32-4.50).

CONCLUSIONS

There was an overall increased risk of Bell's palsy following BNT162b2 vaccination, particularly within the first 14 days after the second dose, but the absolute risk was very low.

Autoimmune conditions following mRNA (BNT162b2) and inactivated (CoronaVac) COVID-19 vaccination: A descriptive cohort study among 1.1 million vaccinated people in Hong Kong

BACKGROUND

Concerns regarding the autoimmune safety of COVID-19 vaccines may negatively impact vaccine uptake. We aimed to describe the incidence of autoimmune conditions following BNT162b2 and CoronaVac vaccination and compare these with age-standardized incidence rates in non-vaccinated individuals.

METHODS

This is a descriptive cohort study conducted in public healthcare service settings. Territory-wide longitudinal electronic medical records of Hong Kong Hospital Authority users (≥16 years) were linked with COVID-19 vaccination records between February 23, 2021 and June 30, 2021. We classified participants into first/second dose BNT162b2 groups, first/second dose CoronaVac groups and non-vaccinated individuals for incidence comparison. The study outcomes include hospitalized autoimmune diseases (16 types of immune-mediated diseases across six body systems) within 28 days after first and second dose of vaccination. Age-standardized incidence rate ratios (IRRs) with exact 95% confidence intervals (CIs) were estimated using Poisson distribution.

RESULTS

This study included around 3.9 million Hong Kong residents, of which 1,122,793 received at least one dose of vaccine (BNT162b2: 579,998; CoronaVac: 542,795), and 721,588 completed two doses (BNT162b2: 388,881; CoronaVac: 332,707). Within 28 days following vaccination, cumulative incidences for all autoimmune conditions were below 9 per 100,000 persons, for both vaccines and both doses. None of the age-standardized incidence rates were significantly higher than the non-vaccinated individuals, except for an observed increased incidence of hypersomnia following the first dose of BNT162b2 (standardized IRR: 1.47; 95% CI: 1.10-1.94).

CONCLUSIONS

Autoimmune conditions requiring hospital care are rare following mRNA and inactivated COVID-19 vaccination with similar incidence to non-vaccinated individuals. The association between first dose BNT162b2 vaccination and immune-related sleeping disorders requires further research. Population-based robust safety surveillance is essential to detect rare and unexpected vaccine safety events.

Adverse events of special interest and mortality following vaccination with mRNA (BNT162b2) and inactivated (CoronaVac) SARS-CoV-2 vaccines in Hong Kong: A retrospective study

BACKGROUND

Safety monitoring of coronavirus disease 2019 (COVID-19) vaccines is crucial during mass vaccination rollout to inform the choice of vaccines and reduce vaccine hesitancy. Considering the scant evidence directly comparing the safety profiles of mRNA and inactivated SARS-CoV-2 vaccines, this territory-wide cohort study aims to compare the incidence of various adverse events of special interest (AESIs) and all-cause mortality between CoronaVac (inactivated vaccine) and BNT162b2 (mRNA-based vaccine). Our results can help vaccine recipients make an informed choice.

METHODS AND FINDINGS

A retrospective, population-based cohort of individuals who had received at least 1 dose of BNT162b2 or CoronaVac from 23 February to 9 September 2021 in Hong Kong, and had data linkage to the electronic medical records of the Hong Kong Hospital Authority, were included. Those who had received mixed doses were excluded. Individuals were observed from the date of vaccination (first or second dose) until mortality, second dose vaccination (for first dose analysis), 21 days after vaccination, or 30 September 2021, whichever came first. Baseline characteristics of vaccinated individuals were balanced between groups using propensity score weighting. Outcome events were AESIs and all-cause mortality recorded during 21 days of post-vaccination follow-up after each dose, except anaphylaxis, for which the observation period was restricted to 2 days after each dose. Incidence rate ratios (IRRs) of AESIs and mortality comparing between CoronaVac and BNT162b2 recipients were estimated after each dose using Poisson regression models. Among 2,333,379 vaccinated individuals aged 18 years or above, the first dose analysis included 1,308,820 BNT162b2 and 955,859 CoronaVac recipients, while the second dose analysis included 1,116,677 and 821,560 individuals, respectively. The most frequently reported AESI among CoronaVac and BNT162b2 recipients was thromboembolism (first dose: 431 and 290 per 100,000 person-years; second dose: 385 and 266 per 100,000 person-years). After the first dose, incidence rates of overall AESIs (IRR = 0.98, 95% CI 0.89-1.08, p = 0.703) and mortality (IRR = 0.96, 95% CI 0.63-1.48, p = 0.868) associated with CoronaVac were generally comparable to those for BNT162b2, except for Bell palsy (IRR = 1.95, 95% CI 1.12-3.41, p = 0.018), anaphylaxis (IRR = 0.34, 95% CI 0.14-0.79, p = 0.012), and sleeping disturbance or disorder (IRR = 0.66, 95% CI 0.49-0.89, p = 0.006). After the second dose, incidence rates of overall AESIs (IRR = 0.97, 95% CI 0.87-1.08, p = 0.545) and mortality (IRR = 0.85, 95% CI 0.51-1.40, p = 0.516) were comparable between CoronaVac and BNT162b2 recipients, with no significant differences observed for specific AESIs. The main limitations of this study include residual confounding due to its observational nature, and the possibility of its being underpowered for some AESIs with very low observed incidences.

CONCLUSIONS

In this study, we observed that the incidences of AESIs (cumulative incidence rate of 0.06%-0.09%) and mortality following the first and second doses of CoronaVac and BNT162b2 vaccination were very low. The safety profiles of the vaccines were generally comparable, except for a significantly higher incidence rate of Bell palsy, but lower incidence rates of anaphylaxis and sleeping disturbance or disorder, following first dose CoronaVac versus BNT162b2 vaccination. Our results could help inform the choice of inactivated COVID-19 vaccines, mainly administered in low- and middle-income countries with large populations, in comparison to the safety of mRNA vaccines. Long-term surveillance on the safety profile of COVID-19 vaccines should continue.

Effects of spike protein and toxin-like peptides found in COVID-19 patients on human 3D neuronal/glial model undergoing differentiation: possible implications for SARS-CoV-2 impact on brain development

The possible neurodevelopmental consequences of SARS-CoV-2 infection are presently unknown. In utero exposure to SARS-CoV-2 has been hypothesized to affect the developing brain, possibly disrupting neurodevelopment of children. Spike protein interactors, such as ACE2, have been found expressed in the fetal brain, and could play a role in potential SARS-CoV-2 fetal brain pathogenesis. Apart from the possible direct involvement of SARS-CoV-2 or its specific viral components in the occurrence of neurological and neurodevelopmental manifestations, we recently reported the presence of toxin-like peptides in plasma, urine and fecal samples specifically from COVID-19 patients. In this study, we investigated the possible neurotoxic effects elicited upon 72-hour exposure to human relevant levels of recombinant spike protein, toxin-like peptides found in COVID-19 patients, as well as a combination of both in 3D human iPSC-derived neural stem cells differentiated for either 2 weeks (short-term) or 8 weeks (long-term, 2 weeks in suspension + 6 weeks on MEA) towards neurons/glia. Whole transcriptome and qPCR analysis revealed that spike protein and toxin-like peptides at non-cytotoxic concentrations differentially perturb the expression of SPHK1, ELN, GASK1B, HEY1, UTS2, ACE2 and some neuronal-, glia- and NSC-related genes critical during brain development. Additionally, exposure to spike protein caused a decrease of spontaneous electrical activity after two days in long-term differentiated cultures. The perturbations of these neurodevelopmental endpoints are discussed in the context of recent knowledge about the key events described in Adverse Outcome Pathways relevant to COVID-19, gathered in the context of the CIAO project (https://www.ciao-covid.net/).