The BNT162b2 mRNA COVID-19 vaccine in adolescents and young adults with cancer: A monocentric experience

Comparison of antibody response to coronavirus disease 2019 vaccination between patients with solid or hematologic cancer patients undergoing chemotherapy

AIM

This study examined the serum antibody response of coronavirus disease 2019 (COVID-19) vaccines in solid and hematologic cancer patients undergoing chemotherapy. Levels of various inflammatory cytokines/chemokines after full vaccination were analyzed.

METHODS

Forty-eight patients with solid cancer and 37 with hematologic malignancy who got fully vaccinated either with severe acute respiratory syndrome coronavirus 2 messenger RNA (mRNA) or vector vaccines or their combination were included. After consecutively collecting blood, immunogenicity was assessed by surrogate virus neutralization test (sVNT), and cytokine/chemokines were evaluated by Meso Scale Discovery assay.

RESULTS

Seropositivity and protective immune response were lower in patients with hematologic cancer compared to those with solid cancers, regardless of vaccine type. Significantly lower sVNT inhibition was observed in patients with hematologic cancer (mean [SD] 45.30 [40.27] %) than in those with solid cancer (mean [SD] 61.78 [34.79] %) (p = 0.047). Heterologous vector/mRNA vaccination was independently and most markedly associated with a higher sVNT inhibition score (p < 0.05), followed by homologous mRNA vaccination. The mean serum levels of tumor necrosis factor α, macrophage inflammatory protein (MIP)-1α, and MIP-1β were significantly higher in patients with hematologic cancers compared to those with solid cancers after the full vaccination. In 36 patients who received an additional booster shot, 29 demonstrated increased antibody titer in terms of mean sVNT (%) (40.80 and 75.21, respectively, before and after the additional dose, p < 0.001).

CONCLUSION

Hematologic cancer patients receiving chemotherapy tended to respond poorly to both COVID-19 mRNA and vector vaccines and had a significantly lower antibody titer compared to those with solid cancers.

Pediatric cancer patients vaccinated against SARS-CoV-2-a clinical and laboratory follow-up

BACKGROUND

Vaccination against SARS-CoV-2 is recommended for cancer patients. However, long-term data on the effectiveness in the pediatric setting are lacking.

METHODS

Pediatric patients < 18 years on active treatment for cancer and without prior SARS-CoV-2 infection received three doses of an mRNA vaccine. The clinical course and humoral and cellular immunity were evaluated at the end of the follow-up period of ≥ 1 year after the third dose of vaccine.

RESULTS

SARS-CoV-2 infection occurred in 17 of 19 analyzed patients (median age 16.5 years) during the follow-up period (median 17 months), but no severe symptoms were seen. At ≥ 1 year after the last SARS-CoV-2 antigen exposure, 4 of 17 patients had received the recommended booster vaccine. At the end of the follow-up period, all evaluable 15 patients had anti-SARS-CoV-2 receptor-binding domain IgG antibodies. Twelve of the 15 patients had neutralizing antibody titers ≥ 1:10 against the Delta variant and 12/15 and 13/15 against the BA.1 and BA.5 variants, respectively. Specific T cells against SARS-CoV-2 antigens were seen in 9/13 patients.

CONCLUSIONS

Most SARS-CoV-2-vaccinated pediatric cancer patients had SARS-CoV-2 infections and limited interest in booster vaccination. At 1 year after the last antigen exposure, which was mostly an infection, humoral immune responses remained strong.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00025254, May 26, 2021.

Bibliometric analysis of scientific papers on adverse reactions to COVID-19 vaccines published between 2019 and 2023

The Coronavirus Disease 2019 (COVID-19) pandemic has now persisted globally for four years, resulting in a staggering death toll of over 4 million individuals. The COVID-19 vaccine has emerged as a highly effective tool in controlling the spread of this virus. However, as the number of individuals receiving COVID-19. In this context, the investigation of adverse reactions related to COVID-19 vaccines holds paramount importance in relevant research. The purpose is to evaluate the current research status regarding adverse reactions associated with COVID-19 vaccines, offering insights for future research. A total of 3,746 articles were included in this analysis, and there has been a notable upward trajectory in the volume of published articles. The CiteSpace v6.1.R6, VOSviewer, SCImago Graphica, and Excel 2019 were employed to analyze and visualize the results. The institutions, countries, journals, authors, co-cited references, and keywords of these articles were analyzed. Furthermore, this study delves into the characteristics of articles on adverse reactions associated with COVID-19 vaccines. It was observed that the number of studies on COVID-19 vaccines has increased year by year since 2019 and witnessed a surge in output in 2021. The vast majority of studies have affirmed the overall safety of COVID-19 vaccines, with adverse reactions tending to be more concentrated in specific diseases. These findings provide valuable ideas for future research in this field and suggest the importance of strengthening international cooperation on adverse reactions to COVID-19 vaccines.

The use of RNA-based treatments in the field of cancer immunotherapy

Over the past several decades, mRNA vaccines have evolved from a theoretical concept to a clinical reality. These vaccines offer several advantages over traditional vaccine techniques, including their high potency, rapid development, low-cost manufacturing, and safe administration. However, until recently, concerns over the instability and inefficient distribution of mRNA in vivo have limited their utility. Fortunately, recent technological advancements have mostly resolved these concerns, resulting in the development of numerous mRNA vaccination platforms for infectious diseases and various types of cancer. These platforms have shown promising outcomes in both animal models and humans. This study highlights the potential of mRNA vaccines as a promising alternative approach to conventional vaccine techniques and cancer treatment. This review article aims to provide a thorough and detailed examination of mRNA vaccines, including their mechanisms of action and potential applications in cancer immunotherapy. Additionally, the article will analyze the current state of mRNA vaccine technology and highlight future directions for the development and implementation of this promising vaccine platform as a mainstream therapeutic option. The review will also discuss potential challenges and limitations of mRNA vaccines, such as their stability and in vivo distribution, and suggest ways to overcome these issues. By providing a comprehensive overview and critical analysis of mRNA vaccines, this review aims to contribute to the advancement of this innovative approach to cancer treatment.

COVID-19 Vaccination Safety Profiles in Patients With Solid Tumour Cancers: A Systematic Review

Vaccination has become an essential means of protection for solid tumour patients against coronavirus disease 2019 (COVID-19). In this systematic review, we sought to identify common safety profiles of the COVID-19 vaccine in patients with solid tumours. A search of Web of Science, PubMed, EMBASE and Cochrane was conducted for studies in English full-text that reported side-effect data experienced by patients with cancer who were at least 12 years old with solid tumours or a recent history of solid tumours after receiving either one or multiple doses of the COVID-19 vaccination. Study quality was assessed with the Newcastle Ottawa Scale criteria. Acceptable study types were retrospective and prospective cohorts, retrospective and prospective observational studies, observational analyses and case series; systematic reviews, meta-analyses and case reports were excluded. Among local/injection site symptoms, the most commonly reported were injection site pain and ipsilateral axillary/clavicular lymphadenopathy, whereas the most commonly reported systemic effects were fatigue/malaise, musculoskeletal symptoms and headache. Most side-effects reported were characterised as mild to moderate. A thorough evaluation of the randomised controlled trials for each featured vaccine led to the conclusion that in the USA and abroad, the safety profile seen in patients with solid tumours is comparable with that seen in the general public.

BNT162b2 COVID-19 Vaccines in Children, Adolescents and Young Adults with Cancer-A 1-Year Follow-Up

(1) Background: Children and young adults with cancer are poorly represented in COVID-19 vaccination studies, and long-term protection conferred by vaccination is not known. (2) Objectives: 1. To determine the adverse effects associated with BNT162B2 vaccination in children and young adults with cancer. 2. To assess its efficacy in stimulating immunological response and in preventing severe COVID-19 disease. (3) Methods: Retrospective single-center study evaluating patients aged 8 to 22 years, with cancer, who underwent vaccination from January 2021 to June 2022. ELISA serologies and serum neutralization were collected monthly from the first injection. Serologies below 26 were considered negative, while those above 264 BAU/mL were considered positive and indicative of protection. Antibodies titers were considered positive above 20. Data on adverse events and infections were collected. (4) Results: 38 patients were included (M/F = 1.7, median age 16 years), of whom 63% had a localized tumor and 76% were undergoing treatment at the time of the first vaccination. Two or three vaccine injections were administered in 90% of patients. Adverse events were mainly systemic and not severe, except for seven grade 3 toxicities. Four cancer-related deaths were reported. Median serology was negative the month following the first vaccination and became protective during the third month. At 3 and 12 months, median serology was 1778 and 6437 BAU/mL, respectively. Serum neutralization was positive in 97% of the patients. COVID-19 infection occurred despite vaccination in 18%; all were mild forms. (5) Conclusions: In children and young adults with cancer, vaccination was well tolerated and conferred effective serum neutralization. COVID-19 infections were mild, and vaccine seroconversion persisted after 12 months in most patients. The value of additional vaccination should be further established.

The impact of the COVID-19 pandemic on perioperative chemotherapy for breast cancer

BACKGROUND

Since it was first reported in December 2019, coronavirus disease 2019 (COVID-19) spread rapidly across the globe resulting in a pandemic. As of August 2022, seven outbreak peaks have been confirmed in Tokyo, and the numbers of new cases in the fifth and later outbreak periods have been far greater than in the preceding periods. This retrospective study examined the impact of the COVID-19 pandemic on perioperative chemotherapy for breast cancer.

METHODS

Patients with breast cancer who received perioperative chemotherapy at the National Cancer Center Hospital East were divided into 2 groups: 120 and 384 patients who started chemotherapy before and during the pandemic, respectively. The incidence of critical events that had potential detrimental effects on the prognosis, such as start of adjuvant chemotherapy ≥91 days after surgery and relative dose intensity of chemotherapy <85% were compared between groups.

RESULTS

No significant difference in the incidence of critical events was found. When stratified by outbreak period, the incidence of critical events was positively correlated with the increasing number of new cases of COVID-19 (r = 0.83, p = 0.04). Moreover, 25/173 patients (14%) who started perioperative chemotherapy during the fifth and sixth outbreak periods developed COVID-19 infection, 80% of whom (20/25) had a delay or interruption to their surgery or other perioperative treatments.

CONCLUSIONS

Although the impact of the COVID-19 pandemic on perioperative chemotherapy on whole groups of patients was not evident when comparing periods before and after the pandemic, the impact is becoming prominent in parallel with increasing numbers of new COVID-19 cases.

COVID-19 coronavirus infection in children: Clinical presentation, diagnosis, vaccination, and treatment

In late 2019, a new subtype of coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (COVID-19 SARS-CoV-2) rapidly spread around the world, causing a global pandemic. Initially, the proportion of confirmed cases among children was relatively small, and it was believed that children were rarely infected. Subsequent observations have shown that in children and adolescents, the infection is either asymptomatic or paucisymptomatic, and therefore the true incidence is underestimated due to the lack of testing. The article systematizes the results of studies on the prevalence, diagnosis, clinical features, vaccination, and treatment of children with a new coronavirus infection COVID-19 SARS-CoV-2. The SARS-CoV-2 positivity rate throughout the peak of the pandemic in children was low compared to adults. Children are not only less likely to become infected with the virus, but they also endure the infection more easily than adults. The mortality rate in children with COVID-19 was <0.5%. In most children, infection is either asymptomatic or paucisymptomatic. Vaccination of children and adolescents is recommended mainly to achieve herd immunity in all age groups. However, there are no convincing data on the duration of the immune response, the level of the required protective antibody titer, as well as on the long-term side effects of vaccination due to the insufficient follow-up period and the uncertainty of the immune response criteria. As information is accumulated on the viral load of children and adolescents, their role in the transmission of the virus, diagnostic approaches in this age group are optimized. The effectiveness of the treatment was tested on patients admitted to the hospital, and recommendations for treatment were developed. Currently, global research efforts are focused on the protection of particularly vulnerable children, the prospects for total childhood vaccination, its effectiveness and safety.

Safety of mRNA-COVID-19 Vaccines in Patients With Thoracic Cancers

BACKGROUND

Pivotal trials of COVID-19 vaccines did not include cancer patients with questions remaining in this population. Particularly in patients with thoracic malignancies receiving anticancer treatments, the safety of these vaccines has so far been little investigated.

METHODS

This is a prospective trial of patients with thoracic cancer receiving anticancer treatments and COVID-19 vaccines at the Division of Thoracic Oncology of European Institute of Oncology between February and September 2021.

RESULTS

A total 207 patients affected by thoracic cancers (199 lung cancers and 8 mesotheliomas) had received Covid-19 vaccines (206 mRNA vaccines and 1 virus-vectored vaccine). The majority of patients had at least one comorbidity (76.3%). They were concomitantly treating with targeted therapy (TT) (45.9%), immunotherapy (IO) (22.7%), and chemotherapy (CT) (14%). A total of 64 AEs (15.6%) were observed after administration of Sars-Cov-2 vaccine. The majority of AEs were grade 1 [G1] (6.3%) and G2 (8.8%), only two events were G3 (0.5%). The median follow-up was 9 months (range 1-22 months), during this follow-up 21 patients (10.1%) had a positive nasal swab, most of the patients were asymptomatic (67%) and the symptomatic ones (33%) had mild symptoms and fewer complications and hospitalizations.

CONCLUSIONS

COVID-19 m-RNA vaccines appear to be safe in the cohort of patients with thoracic malignances in active treatment, including those receiving immunotherapy. Considering the high morbidity and mortality associated with COVID-19 in patients with lung cancer receiving active treatments, our study supports the current vaccine prioritization, third and/or fourth dose, of all cancer patients with active treatment.

Immunogenicity of SARS-CoV-2 vaccines in patients with cancer

Transmission of the SARS-CoV-2 virus and its corresponding disease (COVID-19) has been shown to impose a higher burden on cancer patients than on the general population. Approved vaccines for use include new technology mRNA vaccines such as BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna), and nonreplicating viral vector vaccines such as Ad26.COV2.S (Johnson & Johnson) and AZD1222 (AstraZeneca). Impaired or delayed humoral and diminished T-cell responses are evident in patients with cancer, especially in patients with haematological cancers or those under active chemotherapy. Herein we review the current data on vaccine immunogenicity in cancer patients, including recommendations for current practice and future research.

A systematic review and meta-analysis of immune response against first and second doses of SARS-CoV-2 vaccines in adult patients with hematological malignancies

BACKGROUND

Cancer patients particularly those with hematological malignancies are at higher risk of affecting by severe coronavirus disease 2019 (COVID-19). Due to the immunocompromised nature of the disease and the immunosuppressive treatments, they are more likely to develop less antibody protection; therefore, we aimed to evaluate the immunogenicity of COVID-19 vaccines in patients with hematological malignancies.

METHODS

A comprehensive systematic search was conducted in PubMed, Scopus, and Web of Science databases, as well as Google scholar search engine as of December 10, 2021. Our primary outcomes of interest comprised of estimating the antibody seropositive rate following COVID-19 vaccination in patients with hematological malignancies and to compare it with those who were affected by solid tumors or healthy subjects. The secondary outcomes were to assess the vaccine's immunogenicity based on different treatments, status of the disease, and type of vaccine. After the two-step screening, the data were extracted and the summary measures were calculated using a random-effect model.

RESULTS

A total of 82 articles recording 13,804 patients with a diagnosis of malignancy were included in the present review. The seropositive rates in patients with hematological malignancies after first and second vaccine doses were 30.0% (95% confidence interval (95%CI): 11.9-52.0) and 62.3% (95%CI 56.0-68.5), respectively. These patients were less likely to develop antibody response as compared to cases with solid tumors (RR 0.73, 95%CI 0.67-0.79) and healthy subjects (RR 0.62, 95%CI 0.54-0.71) following complete immunization. Chronic lymphocytic leukemia (CLL) patients had the lowest response rate among all subtypes of hematological malignancies (first dose: 22.0%, 95%CI 13.5-31.8 and second dose: 47.8%, 95%CI 41.2-54.4). Besides, anti-CD20 therapies (5.7%, 95%CI 2.0-10.6) and bruton's tyrosine kinase inhibitors (26.8%, 95%CI 16.9-37.8) represented the lowest seropositiveness post first and second doses, respectively. Notably, patients who were in active status of disease showed lower antibody detection rate compared to those on remission status (RR 0.87, 95%CI 0.76-0.99). Furthermore, lower rate of seropositivity was found in patients received BNT162.b2 compared to ones who received mRNA-1273 (RR 0.89, 95%CI 0.79-0.99).

CONCLUSION

Our findings highlight the substantially low rate of seroprotection in patients with hematological malignancies with a wide range of rates among disease subgroups and different treatments; further highlighting the fact that booster doses might be acquired for these patients to improve immunity against SARS-CoV-2.

Immunologic response, Efficacy, and Safety of Vaccines against COVID-19 Infection in Healthy and immunosuppressed Children and Adolescents Aged 2 - 21 years old: A Systematic Review and Meta-analysis

Children and adolescents form a large proportion of societies and play an important role in the transmission of COVID-19. On the other hand, their education, mental and physical wellness, and safety are compromised which makes vaccination a crucial step to return to normal life. In the current systematic review, the COVID-19 vaccination was evaluated in a total of 50,148 children and adolescents in 22 published studies and 5,279 participants in two ongoing clinical trials. The study was registered in the PROSPERO with the ID# CRD42022303615. Data were collected about multiple vaccines including BNT162b2 (Pfizer), mRNA-1273 (Moderna), JNJ-78436735 (Johnson and Johnson), CoronaVac (Sinovac), BBIBP-CorV (Sinopharm), adenovirus type-5-vectored vaccine, ZyCov-D, and BBV152 (COVAXIN). The immune response and efficacy of such vaccines were 96% - 100% in healthy children and adolescents and were also acceptable in those with underlying diseases and suppressed immune systems. The current systematic review revealed favorable safety profiles of employed vaccines in children and adolescents; however, adverse reactions such as myocarditis and myopericarditis were reported which were transient and resolved entirely. Consequently, vaccinating children and adolescents aged 2 - 21 years old is beneficial to abort the COVID-19 pandemic. Moreover, the risk-benefit assessments revealed favorable results for vaccinating children and adolescents, especially those with underlying diseases and immunosuppressed conditions, alongside adults to prevent transmission, severe infection, negative outcomes, and new variants formation. Also, according to the meta-analysis, the efficacy and immune response of vaccines after the first and second doses were 91% and 92%, respectively. Meanwhile, overall immune response for all vaccines was 95% and 91% for Pfizer vaccine.

Longitudinal Immune Response to 3 Doses of Messenger RNA Vaccine Against Coronavirus Disease 2019 (COVID-19) in Pediatric Patients Receiving Chemotherapy for Cancer

Our study in 21 pediatric cancer patients demonstrates that 3 doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA vaccine (BioNTech/Pfizer) elicited both humoral and cellular immunity in most patients during chemotherapy. Immunity was stronger in children with solid tumors and during maintenance therapy compared to those with hematological malignancies or during intensive chemotherapy. Clinical Trials Registration.ȃGerman Registry for Clinical Trials (DRKS00025254).

SARS-CoV-2 vaccine safety in adolescents with inflammatory rheumatic and musculoskeletal diseases and adults with juvenile idiopathic arthritis: data from the EULAR COVAX physician-reported registry

Background

There is a lack of data on SARS-CoV-2 vaccination safety in children and young people (CYP) with rheumatic and musculoskeletal diseases (RMDs). Current vaccination guidance is based on data from adults with RMDs or CYP without RMDs.

Objectives

To describe the safety of SARS-COV-2 vaccination in adolescents with inflammatory RMDs and adults with juvenile idiopathic arthritis (JIA).

Methods

We described patient characteristics, flares and adverse events (AEs) in adolescent cases under 18 with inflammatory RMDs and adult cases aged 18 or above with JIA submitted to the European Alliance of Associations for Rheumatology COVAX registry.

Results

A total of 110 cases were reported to the registry. Thirty-six adolescent cases were reported from four countries, most with JIA (42%). Over half (56%) reported early reactogenic-like AEs. One mild polyarthralgia flare and one serious AE of special interest (malaise) were reported. No CYP reported SARS-CoV-2 infection postvaccination.

Seventy-four adult JIA cases were reported from 11 countries. Almost two-thirds (62%) reported early reactogenic-like AEs and two flares were reported (mild polyarthralgia and moderate uveitis). No serious AEs of special interest were reported among adults with JIA. Three female patients aged 20–30 years were diagnosed with SARS-CoV-2 postvaccination; all fully recovered.

Conclusions

This is an important contribution to research on SARS-CoV-2 vaccine safety in adolescents with RMDs and adults with JIA. It is important to note the low frequency of disease flares, serious AEs and SARS-CoV-2 reinfection seen in both populations, although the dataset is limited by its size.

Pediatric and Adolescent COVID-19 Vaccination Side Effects: A Retrospective Cohort Study of Iranian Teenage group in 2021

To determine the safety and efficacy profile of teenager COVID‐19 vaccination. In this retrospective cohort study, contact numbers of parents of teenagers under 18 years of age referred to a teenager vaccination centers in Tehran‐Iran to receive the corona vaccine were collected, and the following information was obtained via the phones: demographic information, type of vaccine, and the number of doses received, as well as additional information like complications and required treatments. Eleven thousand forty‐two subjects aged 10−18 years, mean age 14.55 ± 1.83 year  including 5374 boys and 5768 girls were investigated. 88.1% received the Sinopharm and 11.9% the Soberana vaccine. General side effects, including fatigue, fever and chills, injection site pain and dizziness, and so forth happened in 2978 cases; 7421 children presented with at least one general or organ‐specific side effect following vaccination, including potentially critical side effects, such as vascular injuries, respiratory complication, and so forth. 0.1% of the subject needed hospital admission. The breakthrough infection happened in 200 individuals. Our study shows that Sinopharm and Soberana (PastoCoVac) COVID‐19 vaccines are generally safe with no serious side effects in less than 18 years old. COVID‐19 infection and reinfection can occur after vaccination, but the incidence is actually tolerable and significantly lower than in the unvaccinated group.

Only 0.1% of the children with side effects related to vaccination need hospital admission.

Regarding the ABO group, +A and then +O were the dominant blood group that developed COVID‐19.

In total, 412 children developed major side effects (observed in 3.73% of all population and account for 5.5% of all observed side effects).

In total, 3289 children developed general side effects following vaccination (0.2978 i.e., 2978 cases per 10 000 vaccinated children or about 30% of vaccinated children).

There were 7421 children (67%) with at least one general or organ‐specific side effect following vaccination, including dermatological, gastrointestinal, respiratory, joint‐related, neurological, cardiovascular, and renal side effects following vaccination.

All children who developed COVID‐19 after vaccination had a previous history of COVID‐19.

There is no difference regarding the development of COVID‐19 after vaccination between the two vaccines of Sinopharm and Soberana.

Only 1.8% of the children developed COVID‐19 after vaccination (Sinopharm [1.9%] and Soberana [1.5%]).

After receiving both doses, the chance of developing COVID‐19 was the lowest.

Regarding general side effects, fatigue, pain, and dizziness were higher in the Sinopharm group compared to the Soberana group.

Soberana shows early side effects compared to Sinopharm.

Safety of COVID-19 vaccines and disease flares after vaccines in children with rheumatic disease

OBJECTIVES

Wide spread availability of safe and effective vaccines for COVID-19 in all countries is the best hope to end the COVID-19 pandemic. However, in developing countries, the hesitancy of the society about vaccination is an important problem in terms of public health. This study aimed to investigate the acceptability and tolerability of COVID-19 vaccines in the pediatric population diagnosed with rheumatic disease, as well as the attitudes towards these vaccines.

METHODS

This is an observational, cross sectional, single center study. Pediatric patients with at least one diagnosis of rheumatic disease were included in this study to investigate patient and family acceptability and safety of COVID-19 vaccines.

RESULTS

A total of 228 patients with rheumatic disease were included in this study. Ninety nine (43.4%) of the patients were juvenile idiopathic arthritis. One hundred and five (46%) of the patients were using biological agent treatment for their rheumatic disease, whereas 123 (54%) of the patients were not. No serious adverse effect related to the COVID-19 vaccine were observed in any of the patients. No disease activation was observed in any of them.

CONCLUSION

There are only a few studies evaluating of the safety and disease flare of COVID-19 vaccines in children with rheumatic disease. Although this study has some limitations, such as the small sample size of patients with different diagnoses, it appears that there is no increase in COVID-19 vaccination-related harms in the patients with rheumatic disease.

COVID-19 Vaccination in Patients With Malignancy; A Systematic Review and Meta-Analysis of the Efficacy and Safety

Background

Data on the efficacy and safety of COVID-19 vaccines in patients with malignancy are immature. In this paper, we assessed the literature involving the use of COVID-19 vaccines in cancer patients and reported the seroconversion rates as the main outcome and severity of COVID-19 infection and side effects following COVID-19 vaccination as the secondary outcomes.

Methods

A systematic review with meta-analysis was performed. Searches were conducted in electronic websites, databases, and journals, including Scopus, PubMed, Embase, and Web of Science from January 01, 2019, to November 30, 2021. Studies reporting data on the safety and efficacy of COVID vaccine in cancer patients using any human samples were included. The risk of bias was assessed using the NEWCASTLE-OTTAWA scale in the included studies.

Results

A total of 724 articles were identified from databases, out of which 201 articles were duplicates and were discarded. Subsequently, 454 articles were excluded through initial screening of the titles and abstracts. Moreover, 41 studies did not report the precise seroconversion rate either based on the type of cancer or after injection of a second dose of COVID vaccine. Finally, 28 articles met all the inclusion criteria and were included in this systematic review. The overall seroconversion rates after receiving a second dose of COVID-19 vaccine, based on type of cancer were 88% (95% CI, 81%-92%) and 70% (95% CI, 60%-79%) in patients with solid tumors and hematologic malignancies, respectively.

Conclusion

Overall, we conclude that vaccination against COVID-19 in patients with active malignancies using activated and inactivated vaccines is a safe and tolerable procedure that is also accompanied by a high efficacy.

Recent developments in SARS-CoV-2 vaccines: A systematic review of the current studies

Designing and manufacturing efficient vaccines against coronavirus disease 2019 (COVID-19) is a major objective. In this systematic review, we aimed to evaluate the most important vaccines under construction worldwide, their efficiencies and clinical results in healthy individuals and in those with specific underlying diseases. We conducted a comprehensive search in PubMed, Scopus, EMBASE, and Web of Sciences by 1 December 2021 to identify published research studies. The inclusion criteria were publications that evaluated the immune responses and safety of COVID-19 vaccines in healthy individuals and in those with pre-existing diseases. We also searched the VAERS database to estimate the incidence of adverse events of special interest (AESI) post COVID-19 vaccination. Almost all investigated vaccines were well tolerated and developed good levels of both humoural and cellular responses. A protective and efficient humoural immune response develops after the second or third dose of vaccine and a longer interval (about 28 days) between the first and second injections of vaccine could induce higher antibody responses. The vaccines were less immunogenic in immunocompromised patients, particularly those with haematological malignancies. In addition, we found that venous and arterial thrombotic events, Bell's palsy, and myocarditis/pericarditis were the most common AESI. The results showed the potency of the SARS-CoV-2 vaccines to protect subjects against disease. The provision of further effective and safe vaccines is necessary in order to reach a high coverage of immunisation programs across the globe and to provide protection against infection itself.

The Importance of Vaccination in the Context of the COVID-19 Pandemic: A Brief Update Regarding the Use of Vaccines

The COVID-19 pandemic has led the world to undertake the largest vaccination campaign in human history. In record time, unprecedented scientific and governmental efforts have resulted in the acquisition of immunizers utilizing different technologies (nucleotide acids, viral vectors, inactivated and protein-based vaccines). Currently, 33 vaccines have already been approved by regulatory agencies in different countries, and more than 10 billion doses have been administered worldwide. Despite the undeniable impact of vaccination on the control of the pandemic, the recurrent emergence of new variants of interest has raised new challenges. The recent viral mutations precede new outbreaks that rapidly spread at global proportions. In addition, reducing protective efficacy rates have been observed among the main authorized vaccines. Besides these issues, several other crucial issues for the appropriate combatting of the pandemic remain uncertain or under investigation. Particularly noteworthy issues include the use of vaccine-boosting strategies to increase protection; concerns related to the long-term safety of vaccines, child immunization reliability and uncommon adverse events; the persistence of the virus in society; and the transition from a pandemic to an endemic state. In this review, we describe the updated scenario regarding SARS-CoV-2 variants and COVID-19 vaccines. In addition, we outline current discussions covering COVID-19 vaccine safety and efficacy, and the future pandemic perspectives.

COVID-19 vaccination in cancer patients: a narrative review

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected over 220 million individuals worldwide, and has been shown to cause increased disease severity and mortality in patients with active cancer versus healthy individuals. Vaccination is important in reducing COVID-19-associated morbidity and mortality. Thus, the aim of this article was to review the existing knowledge on effectiveness, immunogenicity and safety of COVID-19 vaccines in patients with cancer. Fifty-four articles were included following a search of PubMed and Google Scholar databases for studies published between January 2020 and September 2021 that investigated humoral and cell-mediated immune responses following COVID-19 vaccination in patients with cancer. Immunogenicity of vaccines was found to be lower in patients with cancer versus healthy individuals, and humoral immune responses were inferior in those with haematological versus solid cancers. Patient-, disease-, and treatment-related factors associated with poorer vaccine responses should be identified and corrected or mitigated when possible. Consideration should be given to offering patients with cancer second doses of COVID vaccine at shorter intervals than in healthy individuals. Patients with cancer warrant a third vaccine dose and must be prioritized in vaccination schedules. Vaccine adverse effect profiles are comparable between patients with cancer and healthy individuals.

Consensus on COVID-19 Vaccination in Pediatric Oncohematological Patients, on Behalf of Infectious Working Group of Italian Association of Pediatric Hematology Oncology

Vaccines represent the best tool to prevent the severity course and fatal consequences of the pandemic by the new Coronavirus 2019 infection (SARS-CoV-2). Considering the limited data on vaccination of pediatric oncohematological patients, we developed a Consensus document to support the Italian pediatric hematological oncological (AIEOP) centers in a scientifically correct communication with families and patients and to promote vaccination. The topics of the Consensus were: SARS-CoV-2 infection and disease (COVID-19) in the pediatric subjects; COVID-19 vaccines (type, schedule); who and when to vaccinate; contraindications and risk of serious adverse events; rare adverse events; third dose and vaccination after COVID-19; and other general prevention measures. Using the Delphi methodology for Consensus, 21 statements and their corresponding rationale were elaborated and discussed with the representatives of 31 centers, followed by voting. A high grade of Consensus was obtained on topics such as the potential risk of severe COVID-19 outcome in pediatric oncohematological patients, the need for vaccination as a preventative measure, the type, schedule and booster dose of vaccine, the eligibility of the patients for vaccination, and the timing, definition, and management of contraindications and serious adverse events, and other general prevention measures. All 21 of the statements were approved. This consensus document highlights that children and adolescents affected by hematological and oncological diseases are a fragile category. Vaccination plays an important role to prevent COVID-19, to permit the regular administration of chemotherapy or other treatments, to perform control visits and hospital admissions, and to prevent treatment delays.

An Update on the Status of Vaccine Development for SARS-CoV-2 Including Variants. Practical Considerations for COVID-19 Special Populations

The progress in the development of various vaccine platforms against SARS-CoV-2 have been rather remarkable owing to advancement in molecular and biologic sciences. Most of the current vaccines and those in development focus on targeting the viral spike proteins by generating antibodies of varying spectrum. These vaccines represent a variety of platforms including whole virus vaccines, viral vector vaccines, nucleic acid vaccines representing RNA, DNA, and their hybrid forms.The therapeutic efficacy of these vaccines varies owing to their pharmacodynamic individualities. COVID-19 variants are capable of inducing different pathologic responses and some of which may be resistant to antibodies generated by current vaccines. The current clinical use of these vaccines has been through emergency use authorization until recently. Moreover, the efficacy and safety of these vaccines have been tested in substantial numbers of individuals but studies in special populations that better reflect the global population are pending results. These specialized populations include young children, immunocompromised patients, pregnant individuals, and other specialized groups. Combination approaches, molecularly modified vaccination approaches, and vaccines conferring longer periods of immunity are being currently being investigated, as well as pharmacovigilance studies.The continual transformation of SARS-CoV-2 and its variants are of concern along with the breakthrough infections. These considerations pose new challenges for the development of vaccination platforms. For this purpose, booster doses, combination vaccine approaches, and other modalities are being discussed. This review provides an updated account of currently available vaccines and those in advanced development with reference to their composition and mechanisms of action.A discussion on the use of vaccines in special populations including immunocompromised patients, pregnant women and other specialized populations are also included.

COVID-19 in Children with Cancer

PURPOSE OF REVIEW

This study aims to describe what is currently known about how children with cancer have been affected by the COVID-19 pandemic, including morbidity and mortality, interruptions in cancer care and delays in diagnosis, and psychosocial effects. Here we summarize the literature on how this patient population has fared during the pandemic, reviewing multiple smaller reports along with two large registries.

RECENT FINDINGS

Although children with cancer generally have better outcomes with COVID-19 infection than adults with cancer, their risks of hospitalization, ICU admission, and death are greatly increased compared to the general pediatric population. There are socioeconomic and ethnic disparities present in these effects. Children with cancer experience significant risks from the COVID-19 pandemic. It has yet to be seen how delays and interruptions of cancer treatment and direct organ toxicities caused by the virus itself may affect long-term outcomes in these patients.

Immunological and clinical efficacy of COVID-19 vaccines in immunocompromised populations: a systematic review

BACKGROUND

Available data show that COVID-19 vaccines may be less effective in immunocompromised populations, who are at increased risk of severe COVID-19.

OBJECTIVES

We conducted a systematic review of literature to assess immunogenicity, efficacy and effectiveness of COVID-19 vaccines in immunocompromised populations.

DATA SOURCES

We searched Medline and Embase databases.

STUDY ELIGIBILITY CRITERIA, PATIENTS, INTERVENTIONS

We included studies of COVID-19 vaccines after complete vaccination in immunocompromised patients until 31 August 2021. Studies with <10 patients, safety data only and case series of breakthrough infections were excluded.

METHODS

Risk of bias was assessed via the tool developed by the National Institutes of Health on interventional and observational studies. Immunogenicity was assessed through non-response rate defined as no anti-SARS-CoV-2 spike protein antibodies, efficacy and effectiveness by the relative reduction in risk of SARS-CoV-2 infection or COVID-19. We collected factors associated with the risk of non-response. We presented collected data by immunosuppression type.

RESULTS

We screened 5917 results, included 162 studies. There were 157 on immunogenicity in 25 209 participants, including 7835 cancer or haematological malignancy patients (31.1%), 6302 patients on dialysis (25.0%), 5974 solid organ transplant recipients (23.7%) and 4680 immune-mediated disease patients (18.6%). Proportion of non-responders seemed higher among solid organ transplant recipients (range 18-100%) and patients with haematological malignancy (range 14-61%), and lower in patients with cancer (range 2-36%) and patients on dialysis (range 2-30%). Risk factors for non-response included older age, use of corticosteroids, immunosuppressive or anti-CD20 agent. Ten studies evaluated immunogenicity of an additional dose. Five studies evaluated vaccine efficacy or effectiveness: three on SARS-CoV-2 infection (range 71-81%), one on COVID-19-related hospitalization (62.9%), one had a too small sample size.

CONCLUSIONS

This systematic review highlights the risk of low immunogenicity of COVID-19 vaccines in immunocompromised populations, especially solid organ transplant recipients and patients with haematological malignancy. Despite lack of vaccine effectiveness data, enhanced vaccine regimens may be necessary.

COVID-19 Vaccination in Cancer Patients Older Than 70 Years Undergoing Active Treatment. Seroconversion Rate and Safety

Patients with cancer have a high risk of intubation, intensive care unit admission, or death from the coronavirus disease (COVID-19); age and comorbidities are additional risk factors. Vaccination is effective against COVID-19; however, patients with cancer have been excluded from pivotal clinical trials for COVID-19 vaccines. Data on COVID-19 vaccination in cancer patients who are older are lacking. This observational study was conducted to evaluate the seropositivity rate and safety of a two-dose regimen of the BNT162b2 or mRNA1273 vaccine in older patients (age ≥ 70 years) with solid tumors or with hematological malignances who are undergoing active anticancer treatment or whose treatment has been terminated within 6 months of vaccination. The control group was composed of healthy volunteers that were age-matched with the patient group. The primary endpoint was the seropositivity rate, and the secondary endpoints were safety, the factors influencing seroconversion, the IgG titers of patients versus healthy volunteers, and post-vaccine COVID-19 infection between 20 March 2021 and 14 July 2021. At our Institution (Oncology and Hematology Department, Hospital of Piacenza, North Italy), 443 patients with cancer underwent a program for COVID-19 vaccination; 115 (25.95%) were older than 70 (range 71–86 years) and form the basis of this study. All 115 patients accepted the vaccination. There were 64 female patients (55.65%), 94 patients (81.74%) with solid tumors, and 21 patients (18.26%) with hematological malignances. The primary endpoint of seropositivity was observed in 75 patients (65.22%)—70.21% in patients with solid tumors and 42.86% in patients with hematological malignances—versus in 100% of patients in the control group. Of the secondary endpoints, no grade 3–4 side effects and no COVID-19 infections were reported. The factor influencing seroconversion was the type of cancer. The patients’ median IgG titers were significantly lower than in the control groups. The COVID-19 vaccines BNT162b2 and mRNA1273 were effective and safe among older patients with cancer when administered in real-world conditions.

Multimorbidity and adverse events of special interest associated with Covid-19 vaccines in Hong Kong

Prior research using electronic health records for Covid-19 vaccine safety monitoring typically focuses on specific disease groups and excludes individuals with multimorbidity, defined as ≥2 chronic conditions. We examine the potential additional risk of adverse events 28 days after the first dose of CoronaVac or Comirnaty imposed by multimorbidity. Using a territory-wide public healthcare database with population-based vaccination records in Hong Kong, we analyze a retrospective cohort of patients with chronic conditions. Thirty adverse events of special interest according to the World Health Organization are examined. In total, 883,416 patients are included and 2,807 (0.3%) develop adverse events. Results suggest vaccinated patients have lower risks of adverse events than unvaccinated individuals, multimorbidity is associated with increased risks regardless of vaccination, and the association of vaccination with adverse events is not modified by multimorbidity. To conclude, we find no evidence that multimorbidity imposes extra risks of adverse events following Covid-19 vaccination.

COVID-19 Vaccinations: Perceptions and Behaviours in People with Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic disease that causes recurrent respiratory infections. People with PCD may be at higher risk of severe coronavirus disease 2019 (COVID-19), and therefore vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important. We studied vaccination willingness, speed of vaccination uptake, side effects, and changes in social contact behaviour after vaccination in people with PCD. We used data from COVID-PCD, an international participatory cohort study. A COVID-19 vaccination questionnaire was emailed to participants in May 2021 and 423 participants from 31 countries replied (median age: 30 years, range 1-85 years; 261 (62%) female). Vaccination uptake and willingness were high, with 273 of 287 adults (96%) being vaccinated or willing to be in June 2021; only 4% were hesitant. The most common reason for hesitancy was fear of side effects, reported by 88%. Mild side effects were common, but no participant reported severe side effects. Half of the participants changed their social behaviour after vaccination by seeing friends and family more often. The high vaccination willingness in the study population might reflect the extraordinary effort taken by PCD support groups to inform people about COVID-19 vaccination. Clear and specific information and involvement of representatives is important for high vaccine uptake.

Learning through a Pandemic: The Current State of Knowledge on COVID-19 and Cancer

The ongoing COVID-19 pandemic has left patients with current or past history of cancer facing disparate consequences at every stage of the cancer trajectory. This comprehensive review offers a landscape analysis of the current state of the literature on COVID-19 and cancer including the immune response to COVID-19, risk factors for severe disease, and impact of anticancer therapies. We also review the latest data on treatment of COVID-19 and vaccination safety and efficacy in patients with cancer, as well as impact of the pandemic on cancer care, including the urgent need for rapid evidence generation and real-world study designs.

Evaluation of COVID-19 vaccine response in patients with cancer: An interim analysis

Background

Efficacy and safety data of COVID-19 vaccines among cancer populations have been limited; however, preliminary data from recent studies have emerged regarding their immunogenicity and safety in this population. In this review, we examined current peer-reviewed publications containing serological and safety data after COVID-19 vaccination of patients with cancer.

Methods

This analysis examined 21 studies with a total of 5012 patients with cancer, of which 2676 (53%) had haematological malignancies, 2309 (46%) had solid cancers and 739 were healthy controls. Serological responses by anti–SARS-CoV-2 spike protein S1/S2 immunoglobulin G antibody levels and post-vaccination patient questionnaires regarding vaccine-related side-effects after the first and second dose were collected and analysed.

Results

In general, a single dose of the COVID-19 vaccine yields weaker and heterogeneous serological responses in both patients with haematological and solid malignancies. On receiving a second dose, serological response rates indicate a substantial increase in seropositivity to the SARS-CoV-2 spike protein in all cancer cohorts, but antibody titres remain reduced in comparison with healthy controls. Furthermore, seroconversion in patients with haematological malignancies was significantly lower than that in patients with solid tumours. COVID-19 vaccines are safe and well-tolerated in patients with cancer based on current data of local and systemic effects.

Conclusion

Together, these data support the prioritisation of patients with cancer to receive their first and second doses to minimise the risk of COVID-19 infection and severe complications in this vulnerable population. Additional prophylactic measures must be considered for high-risk patients where current vaccination programs may not mount sufficient protection against SARS-CoV-2 infection.

Effectiveness and safety of SARS-CoV-2 vaccine in real-world studies: a systematic review and meta-analysis

BACKGROUND

To date, coronavirus disease 2019 (COVID-19) becomes increasingly fierce due to the emergence of variants. Rapid herd immunity through vaccination is needed to block the mutation and prevent the emergence of variants that can completely escape the immune surveillance. We aimed to systematically evaluate the effectiveness and safety of COVID-19 vaccines in the real world and to establish a reliable evidence-based basis for the actual protective effect of the COVID-19 vaccines, especially in the ensuing waves of infections dominated by variants.

METHODS

We searched PubMed, Embase and Web of Science from inception to July 22, 2021. Observational studies that examined the effectiveness and safety of SARS-CoV-2 vaccines among people vaccinated were included. Random-effects or fixed-effects models were used to estimate the pooled vaccine effectiveness (VE) and incidence rate of adverse events after vaccination, and their 95% confidence intervals (CI).

RESULTS

A total of 58 studies (32 studies for vaccine effectiveness and 26 studies for vaccine safety) were included. A single dose of vaccines was 41% (95% CI: 28-54%) effective at preventing SARS-CoV-2 infections, 52% (31-73%) for symptomatic COVID-19, 66% (50-81%) for hospitalization, 45% (42-49%) for Intensive Care Unit (ICU) admissions, and 53% (15-91%) for COVID-19-related death; and two doses were 85% (81-89%) effective at preventing SARS-CoV-2 infections, 97% (97-98%) for symptomatic COVID-19, 93% (89-96%) for hospitalization, 96% (93-98%) for ICU admissions, and 95% (92-98%) effective for COVID-19-related death, respectively. The pooled VE was 85% (80-91%) for the prevention of Alpha variant of SARS-CoV-2 infections, 75% (71-79%) for the Beta variant, 54% (35-74%) for the Gamma variant, and 74% (62-85%) for the Delta variant. The overall pooled incidence rate was 1.5% (1.4-1.6%) for adverse events, 0.4 (0.2-0.5) per 10 000 for severe adverse events, and 0.1 (0.1-0.2) per 10 000 for death after vaccination.

CONCLUSIONS

SARS-CoV-2 vaccines have reassuring safety and could effectively reduce the death, severe cases, symptomatic cases, and infections resulting from SARS-CoV-2 across the world. In the context of global pandemic and the continuous emergence of SARS-CoV-2 variants, accelerating vaccination and improving vaccination coverage is still the most important and urgent matter, and it is also the final means to end the pandemic.

COVID-19 vaccines in adult cancer patients with solid tumours undergoing active treatment: Seropositivity and safety. A prospective observational study in Italy

INTRODUCTION

Patients with cancer are presumed a frail group at high risk of contracting coronavirus disease (COVID-19), and vaccination represents a cornerstone in addressing the COVID-19 pandemic. However, data on COVID-19 vaccination in cancer patients are fragmentary and poor.

METHODS

An observational study was conducted to evaluate the seropositivity rate and safety of a two-dose regimen of the BNT162b2 or messenger RNA-1273 vaccine in adult patients with solid cancer undergoing active anticancer treatment or whose treatment had been terminated within 6 months of the start of the study. The control group was composed of healthy volunteers. Serum samples were evaluated for SARS-COV-2 antibodies before vaccinations and 2-6 weeks after the administration of the second vaccine dose. Primary end-point: seropositivity rate. Secondary end-points: safety, factors influencing seroconversion, IgG titers of patients versus healthy volunteers, COVID-19 infection.

RESULTS

Between 20th March 2021 and 12th June 2021, 293 consecutive patients with cancer-solid tumours underwent a program of COVID-19 vaccinations; of these, 2 patients refused vaccination, 13 patients did not receive the second dose of the vaccine because of cancer progression, and 21 patients had COVID-19 antibodies at baseline and were excluded. The 257 evaluable patients had a median age of 65 years (range 28-86), 66.15% with metastatic disease. Primary end-point: seropositivity rate in patients was 75.88% versus 100% in the control group. Secondary end-points: no Grade 3-4 side-effects, no COVID-19 infections were reported. Patients median IgG titer was significantly lower than in the control group; male sex and active anticancer therapy influenced negative seroconversion. BNT162b2 or messenger RNA-1273 vaccines were immunogenic in cancer patients, showing good safety profile.

Immunogenicity and risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection after Coronavirus Disease 2019 (COVID-19) vaccination in patients with cancer: a systematic review and meta-analysis

Background

Patients with cancer are considered a priority group for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccination given their high risk of contracting severe Coronavirus Disease 2019 (COVID-19). However, limited data exist regarding the efficacy of immunisation in this population. In this study, we assess the immunologic response after COVID-19 vaccination of cancer versus non-cancer population.

Methods

PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases were searched from 01st March 2020 through 12th August 12 2021. Primary end-points were anti-SARS-CoV-2 spike protein (S) immunoglobulin G (IgG) seroconversion rates, T-cell response, and documented SARS-CoV-2 infection after COVID-19 immunisation. Data were extracted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Overall effects were pooled using random-effects models.

Results

This systematic review and meta-analysis included 35 original studies. Overall, 51% (95% confidence interval [CI], 41–62) and 73% (95% CI, 64–81) of patients with cancer developed anti-S IgG above the threshold level after partial and complete immunisation, respectively. Patients with haematologic malignancies had a significantly lower seroconversion rate than those with solid tumours after complete immunisation (65% vs 94%; P < 0.0001). Compared with non-cancer controls, oncological patients were less likely to attain seroconversion after incomplete (risk ratio [RR] 0.45 [95% CI 0.35–0.58]) and complete (RR 0.69 [95% CI 0.56–0.84]) COVID-19 immunisation schemes. Patients with cancer had a higher likelihood of having a documented SARS-CoV-2 infection after partial (RR 3.21; 95% CI 0.35–29.04) and complete (RR 2.04; 95% CI 0.38–11.10) immunisation.

Conclusions

Patients with cancer have an impaired immune response to COVID-19 vaccination compared with controls. Strategies that endorse the completion of vaccination schemes are warranted. Future studies should aim to evaluate different approaches that enhance oncological patients’ immune response.

Safety, Immunogenicity, and Efficacy of COVID-19 Vaccines in Children and Adolescents: A Systematic Review

AIM

To identify the safety, immunogenicity, and protective efficacy of COVID-19 vaccines in children and adolescents.

METHODS

We conducted a systematic review of published studies and ongoing clinical studies related to the safety, immunogenicity, and efficacy of COVID-19 vaccine in children or adolescents (aged < 18 years). Databases including PubMed, Web of Science, WHO COVID-19 database, and China National Knowledge Infrastructure (CNKI) were searched on 23 July 2021. International Clinical Trials Registry Platform (ICTRP) was also searched to identify ongoing studies.

RESULTS

Eight published studies with a total of 2852 children and adolescents and 28 ongoing clinical studies were included. Of the eight published studies, two were RCTs, two case series, and four case reports. The investigated COVID-19 vaccines had good safety profiles in children and adolescents. Injection site pain, fatigue, headache, and chest pain were the most common adverse events. A limited number of cases of myocarditis and pericarditis were reported. The RCTs showed that the immune response to BNT162b2 in adolescents aged 12-15 years was non-inferior to that in young people aged 16-25 years, while with 3 μg CoronaVac injection the immune response was stronger than with 1.5 μg. The efficacy of BNT162b2 was 100% (95% CI: 75.3 to 100), based on one RCT. Of the 28 ongoing clinical studies, twenty-three were interventional studies. The interventional studies were being conducted in fifteen countries, among them, China (10, 43.5%) and United States(9, 39.1%) had the highest number of ongoing trials. BNT162b2 was the most commonly studied vaccine in the ongoing trials.

CONCLUSION

Two COVID-19 vaccines have potential protective effects in children and adolescents, but awareness is needed to monitor possible adverse effects after injection. Clinical studies of the COVID-19 vaccination in children and adolescents with longer follow-up time, larger sample size, and a greater variety of vaccines are still urgently needed.