Vaccine development for mosquito-borne viral diseases.

Mosquito-borne viral diseases are a group of viral illnesses that are predominantly transmitted by mosquitoes, including viruses from the Togaviridae and Flaviviridae families. In recent years, outbreaks caused by Dengue and Zika viruses from the Flaviviridae family, and Chikungunya virus from the Togaviridae family, have raised significant concerns for public health. However, there are currently no safe and effective vaccines available for these viruses, except for CYD-TDV, which has been licensed for Dengue virus. Efforts to control the transmission of COVID-19, such as home quarantine and travel restrictions, have somewhat limited the spread of mosquito-borne viral diseases. Several vaccine platforms, including inactivated vaccines, viral-vector vaccines, live attenuated vaccines, protein vaccines, and nucleic acid vaccines, are being developed to combat these viruses. This review analyzes the various vaccine platforms against Dengue, Zika, and Chikungunya viruses and provides valuable insights for responding to potential outbreaks.

SARS-CoV-2 induces cardiomyocyte apoptosis and inflammation but can be ameliorated by ACE inhibitor Captopril.

Although the clinical manifestation of COVID-19 is mainly respiratory symptoms, approximately 20% of patients suffer from cardiac complications. COVID-19 patients with cardiovascular disease have higher severity of myocardial injury and poor outcomes. The underlying mechanism of myocardial injury caused by SARS-CoV-2 infection remains unclear. Using a non-transgenic mouse model infected with Beta variant (B.1.351), we found that the viral RNA could be detected in lungs and hearts of infected mice. Pathological analysis showed thinner ventricular wall, disorganized and ruptured myocardial fiber, mild inflammatory infiltration, and mild epicardia or interstitial fibrosis in hearts of infected mice. We also found that SARS-CoV-2 could infect cardiomyocytes and produce infectious progeny viruses in human pluripotent stem cell-derived cardiomyocyte-like cells (hPSC-CMs). SARS-CoV-2 infection caused apoptosis, reduction of mitochondrial integrity and quantity, and cessation of beating in hPSC-CMs. In order to dissect the mechanism of myocardial injury caused by SARS-CoV-2 infection, we employed transcriptome sequencing of hPSC-CMs at different time points after viral infection. Transcriptome analysis showed robust induction of inflammatory cytokines and chemokines, up-regulation of MHC class I molecules, activation of apoptosis signaling and cell cycle arresting. These may cause aggravate inflammation, immune cell infiltration, and cell death. Furthermore, we found that Captopril (hypotensive drugs targeting ACE) treatment could alleviate SARS-CoV-2 induced inflammatory response and apoptosis in cardiomyocytes via inactivating TNF signaling pathways, suggesting Captopril may be beneficial for reducing COVID-19 associated cardiomyopathy. These findings preliminarily explain the molecular mechanism of pathological cardiac injury caused by SARS-CoV-2 infection, providing new perspectives for the discovery of antiviral therapeutics.

Comparing T- and B-cell responses to COVID-19 vaccines across varied immune backgrounds.

The emergence of adapted variants of the SARS-CoV-2 virus has led to a surge in breakthrough infections worldwide. A recent analysis of immune responses in people who received inactivated vaccines has revealed that individuals with no prior infection have limited resistance to Omicron and its sub-lineages, while those with previous infections exhibit a significant amount of neutralizing antibodies and memory B cells. However, specific T-cell responses remain largely unaffected by the mutations, indicating that T-cell-mediated cellular immunity can still provide protection. Moreover, the administration of a third dose of vaccine has resulted in a marked increase in the spectrum and duration of neutralizing antibodies and memory B cells in vivo, which has enhanced resistance to emerging variants such as BA.2.75 and BA.2.12.1. These results highlight the need to consider booster immunization for previously infected individuals and the development of novel vaccination strategies. The rapid spread of adapted variants of the SARS-CoV-2 virus presents a significant challenge to global health. The findings from this study underscore the importance of tailoring vaccination strategies based on individual immune backgrounds and the potential need for booster shots to combat emerging variants. Continued research and development are crucial to discovering new immunization strategies that will effectively protect public health against the evolving virus.

SARS-CoV-2 omicron BA.1.1 is highly resistant to antibody neutralization of convalescent serum from the origin strain.

The emergence and rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant (BA.1.1) has attracted global attention. The numerous mutations in the spike protein suggest that it may have altered susceptibility to immune protection elicited by the existing coronavirus disease 2019 (COVID-19) infection. We used a live virus neutralization test and SARS-CoV-2 pseudotype vesicular stomatitis virus vector-based neutralization assay to assess the degree of immune escape efficiency of the original, Delta (B1.617.2), and Omicron strains against the serum antibodies from 64 unvaccinated patients who had recovered from COVID-19 and the results were strongly correlated. The convalescent serum neutralization was more markedly reduced against the Omicron variant (9.4-57.9-fold) than the Delta variant (2.0-4.5-fold) as compared with the original strain. Our results demonstrate the reduced fusion and notable immune evasion capabilities of the Omicron variants, highlighting the importance of accelerating the development of vaccines targeting them.

Plasma cell-free DNA promise monitoring and tissue injury assessment of COVID-19.

Coronavirus 2019 (COVID-19) is a complex disease that affects billions of people worldwide. Currently, effective etiological treatment of COVID-19 is still lacking; COVID-19 also causes damages to various organs that affects therapeutics and mortality of the patients. Surveillance of the treatment responses and organ injury assessment of COVID-19 patients are of high clinical value. In this study, we investigated the characteristic fragmentation patterns and explored the potential in tissue injury assessment of plasma cell-free DNA in COVID-19 patients. Through recruitment of 37 COVID-19 patients, 32 controls and analysis of 208 blood samples upon diagnosis and during treatment, we report gross abnormalities in cfDNA of COVID-19 patients, including elevated GC content, altered molecule size and end motif patterns. More importantly, such cfDNA fragmentation characteristics reflect patient-specific physiological changes during treatment. Further analysis on cfDNA tissue-of-origin tracing reveals frequent tissue injuries in COVID-19 patients, which is supported by clinical diagnoses. Hence, our work demonstrates and extends the translational merit of cfDNA fragmentation pattern as valuable analyte for effective treatment monitoring, as well as tissue injury assessment in COVID-19.

Non-spike and spike-specific memory T cell responses after the third dose of inactivated COVID-19 vaccine.

Background: During the COVID-19 epidemic, vaccination has become the most safe and effective way to prevent severe illness and death. Inactivated vaccines are the most widely used type of COVID-19 vaccines in the world. In contrast to spike-based mRNA/protein COVID-19 vaccines, inactivated vaccines generate antibodies and T cell responses against both spike and non-spike antigens. However, the knowledge of inactivated vaccines in inducing non-spike-specific T cell response is very limited. Methods: In this study, eighteen healthcare volunteers received a homogenous booster (third) dose of the CoronaVac vaccine at least 6 months after the second dose. CD4+ and CD8+ T cell responses against a peptide pool from wild-type (WT) non-spike proteins and spike peptide pools from WT, Delta, and Omicron SARS-CoV-2 were examined before and 1-2 weeks after the booster dose. Results: The booster dose elevated cytokine response in CD4+ and CD8+ T cells as well as expression of cytotoxic marker CD107a in CD8+ T cells in response to non-spike and spike antigens. The frequencies of cytokine-secreting non-spike-specific CD4+ and CD8+ T cells correlated well with those of spike-specific from WT, Delta, and Omicron. Activation-induced markers (AIM) assay also revealed that booster vaccination elicited non-spike-specific CD4+ and CD8+ T cell responses. In addition, booster vaccination produced similar spike-specific AIM+CD4+ and AIM+CD8+ T cell responses to WT, Delta, and Omicron, indicting strong cross-reactivity of functional cellular response between WT and variants. Furthermore, booster vaccination induced effector memory phenotypes of spike-specific and non-spike-specific CD4+ and CD8+ T cells. Conclusions: These data suggest that the booster dose of inactive vaccines broadens both non-spike-specific and spike-specific T cell responses against SARS-CoV-2.

Extending the dosing interval of COVID-19 vaccination leads to higher rates of seroconversion in people living with HIV

Introduction Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is an effective way of protecting individuals from severe coronavirus disease 2019 (COVID-19). However, immune responses to vaccination vary considerably. This study dynamically assessed the neutralizing antibody (NAb) responses to the third dose of the inactivated COVID-19 vaccine administered to people living with human immunodeficiency virus (HIV;PLWH) with different inoculation intervals. Methods A total of 171 participants were recruited: 63 PLWH were placed in cohort 1 (with 3-month interval between the second and third doses), while 95 PLWH were placed in cohort 2 (with 5-month interval between the second and third doses);13 individuals were enrolled as healthy controls (HCs). And risk factors associated with seroconversion failure after vaccination were identified via Cox regression analysis. Results At 6 months after the third vaccination, PLWH in cohort 2 had higher NAb levels (GMC: 64.59 vs 21.99, P < 0.0001) and seroconversion rate (68.42% vs 19.05%, P < 0.0001). A weaker neutralizing activity against the SARSCoV-2 Delta variant was observed (GMT: 3.38 and 3.63, P < 0.01) relative to the wildtype strain (GMT: 13.68 and 14.83) in both cohorts. None of the participants (including HCs or PLWH) could mount a NAb response against Omicron BA.5.2. In the risk model, independent risk factors for NAb seroconversion failure were the vaccination interval (hazed ration [HR]: 0.316, P < 0.001) and lymphocyte counts (HR: 0.409, P < 0.001). Additionally, PLWH who exhibited NAb seroconversion after vaccination had fewer initial COVID-19 symptoms when infected with Omicron. Discussion This study demonstrated that the third vaccination elicited better NAb responses in PLWH, when a longer interval was used between vaccinations. Since post-vaccination seroconversion reduced the number of symptoms induced by Omicron, efforts to protect PLWH with risk factors for NAb seroconversion failure may be needed during future Omicron surges. Clinical trial registration https://beta.clinicaltrials.gov/study/NCT05075070, identifier NCT05075070.

Extending the dosing interval of COVID-19 vaccination leads to higher rates of seroconversion in people living with HIV.

Introduction: Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is an effective way of protecting individuals from severe coronavirus disease 2019 (COVID-19). However, immune responses to vaccination vary considerably. This study dynamically assessed the neutralizing antibody (NAb) responses to the third dose of the inactivated COVID-19 vaccine administered to people living with human immunodeficiency virus (HIV; PLWH) with different inoculation intervals. Methods: A total of 171 participants were recruited: 63 PLWH were placed in cohort 1 (with 3-month interval between the second and third doses), while 95 PLWH were placed in cohort 2 (with 5-month interval between the second and third doses); 13 individuals were enrolled as healthy controls (HCs). And risk factors associated with seroconversion failure after vaccination were identified via Cox regression analysis. Results: At 6 months after the third vaccination, PLWH in cohort 2 had higher NAb levels (GMC: 64.59 vs 21.99, P < 0.0001) and seroconversion rate (68.42% vs 19.05%, P < 0.0001). A weaker neutralizing activity against the SARSCoV-2 Delta variant was observed (GMT: 3.38 and 3.63, P < 0.01) relative to the wildtype strain (GMT: 13.68 and 14.83) in both cohorts. None of the participants (including HCs or PLWH) could mount a NAb response against Omicron BA.5.2. In the risk model, independent risk factors for NAb seroconversion failure were the vaccination interval (hazed ration [HR]: 0.316, P < 0.001) and lymphocyte counts (HR: 0.409, P < 0.001). Additionally, PLWH who exhibited NAb seroconversion after vaccination had fewer initial COVID-19 symptoms when infected with Omicron. Discussion: This study demonstrated that the third vaccination elicited better NAb responses in PLWH, when a longer interval was used between vaccinations. Since post-vaccination seroconversion reduced the number of symptoms induced by Omicron, efforts to protect PLWH with risk factors for NAb seroconversion failure may be needed during future Omicron surges. Clinical trial registration: https://beta.clinicaltrials.gov/study/NCT05075070, identifier NCT05075070.

PrivacyMask: Real-world privacy protection in face ID systems.

Recent works have illustrated that many facial privacy protection methods are effective in specific face recognition algorithms. However, the COVID-19 pandemic has promoted the rapid innovation of face recognition algorithms for face occlusion, especially for the face wearing a mask. It is tricky to avoid being tracked by artificial intelligence only through ordinary props because many facial feature extractors can determine the ID only through a tiny local feature. Therefore, the ubiquitous high-precision camera makes privacy protection worrying. In this paper, we establish an attack method directed against liveness detection. A mask printed with a textured pattern is proposed, which can resist the face extractor optimized for face occlusion. We focus on studying the attack efficiency in adversarial patches mapping from two-dimensional to three-dimensional space. Specifically, we investigate a projection network for the mask structure. It can convert the patches to fit perfectly on the mask. Even if it is deformed, rotated and the lighting changes, it will reduce the recognition ability of the face extractor. The experimental results show that the proposed method can integrate multiple types of face recognition algorithms without significantly reducing the training performance. If we combine it with the static protection method, people can prevent face data from being collected.

A high-throughput fully automatic biosensing platform for efficient COVID-19 detection.

We propose a label-free biosensor based on a porous silicon resonant microcavity and localized surface plasmon resonance. The biosensor detects SARS-CoV-2 antigen based on engineered trimeric angiotensin converting enzyme-2 binding protein, which is conserved across different variants. Robotic arms run the detection process including sample loading, incubation, sensor surface rinsing, and optical measurements using a portable spectrometer. Both the biosensor and the optical measurement system are readily scalable to accommodate testing a wide range of sample numbers. The limit of detection is 100 TCID50/ml. The detection time is 5 min, and the throughput of one single robotic site is up to 384 specimens in 30 min. The measurement interface requires little training, has standard operation, and therefore is suitable for widespread use in rapid and onsite COVID-19 screening or surveillance.

An updated review of SARS-CoV-2 detection methods in the context of a novel coronavirus pandemic.

The World Health Organization has reported approximately 430 million confirmed cases of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), worldwide, including nearly 6 million deaths, since its initial appearance in China in 2019. While the number of diagnosed cases continues to increase, the need for technologies that can accurately and rapidly detect SARS-CoV-2 virus infection at early phases continues to grow, and the Federal Drug Administration (FDA) has licensed emergency use authorizations (EUAs) for virtually hundreds of diagnostic tests based on nucleic acid molecules and antigen-antibody serology assays. Among them, the quantitative real-time reverse transcription PCR (qRT-PCR) assay is considered the gold standard for early phase virus detection. Unfortunately, qRT-PCR still suffers from disadvantages such as the complex test process and the occurrence of false negatives; therefore, new nucleic acid detection devices and serological testing technologies are being developed. However, because of the emergence of strongly infectious mutants of the new coronavirus, such as Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (B.1.1.529), the need for the specific detection of mutant strains is also increasing. Therefore, this article reviews nucleic acid- and antigen-antibody-based serological assays, and compares the performance of some of the most recent FDA-approved and literature-reported assays and associated kits for the specific testing of new coronavirus variants.

Mouse models susceptible to HCoV-229E and HCoV-NL63 and cross protection from challenge with SARS-CoV-2.

Human coronavirus 229E (HCoV-229E) and NL63 (HCoV-NL63) are endemic causes of upper respiratory infections such as the "common cold" but may occasionally cause severe lower respiratory tract disease in the elderly and immunocompromised patients. There are no approved antiviral drugs or vaccines for these common cold coronaviruses (CCCoV). The recent emergence of COVID-19 and the possible cross-reactive antibody and T cell responses between these CCCoV and SARS-CoV-2 emphasize the need to develop experimental animal models for CCCoV. Mice are an ideal experimental animal model for such studies, but are resistant to HCoV-229E and HCoV-NL63 infections. Here, we generated 229E and NL63 mouse models by exogenous delivery of their receptors, human hAPN and hACE2 using replication-deficient adenoviruses (Ad5-hAPN and Ad5-hACE2), respectively. Ad5-hAPN- and Ad5-hACE2-sensitized IFNAR-/- and STAT1-/- mice developed pneumonia characterized by inflammatory cell infiltration with virus clearance occurring 7 d post infection. Ad5-hAPN- and Ad5-hACE2-sensitized mice generated virus-specific T cells and neutralizing antibodies after 229E or NL63 infection, respectively. Remdesivir and a vaccine candidate targeting spike protein of 229E and NL63 accelerated viral clearance of virus in these mice. 229E- and NL63-infected mice were partially protected from SARS-CoV-2 infection, likely mediated by cross-reactive T cell responses. Ad5-hAPN- and Ad5-hACE2-transduced mice are useful for studying pathogenesis and immune responses induced by HCoV-229E and HCoV-NL63 infections and for validation of broadly protective vaccines, antibodies, and therapeutics against human respiratory coronaviruses including SARS-CoV-2.

Neutralizing Antibodies against the SARS-CoV-2 Delta and Omicron BA.1 following Homologous CoronaVac Booster Vaccination.

Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants have reduced susceptibility to neutralization by vaccines. In response to the constantly updated variants, a global vaccine booster vaccination program has been launched. In this study, we detected neutralizing antibody levels against wild-type (WT), Delta (B1.617.2), and Omicron BA.1 viruses in serum after each dose of CoronaVac vaccination. We found that booster vaccination significantly increased the levels of neutralizing antibodies against WT, Delta, and Omicron BA.1. Compared with only one vaccination, neutralizing antibody levels increased by 19.2-21.6-fold after a booster vaccination, whilst two vaccinations only produced a 1.5-3.4-fold increase. Our results support the conclusion that the CoronaVac vaccine booster can increase neutralizing antibody levels and cross-reactivity and enhance the body's ability to effectively resist the infection of new coronavirus variants, emphasizing the need for booster vaccination.

Shared IGHV1-69-encoded neutralizing antibodies contribute to the emergence of L452R substitution in SARS-CoV-2 variants.

SARS-CoV-2 variants continue to emerge facing established herd immunity. L452R, previously featured in the Delta variant, quickly emerged in Omicron subvariants, including BA.4/BA.5, implying a continued selection pressure on this residue. The underlying links between spike mutations and their selective pressures remain incompletely understood. Here, by analyzing 221 structurally characterized antibodies, we found that IGHV1-69-encoded antibodies preferentially contact L452 using germline-encoded hydrophobic residues at the tip of HCDR2 loop. Whereas somatic hypermutations or VDJ rearrangements are required to acquire L452-contacting hydrophobic residues for non-IGHV1-69 encoded antibodies. Antibody repertoire analysis revealed that IGHV1-69 L452-contacting antibody lineages are commonly induced among COVID-19 convalescents but non-IGHV1-69 encoded antibodies exhibit limited prevalence. In addition, we experimentally demonstrated that L452R renders most published IGHV1-69 antibodies ineffective. Furthermore, we found that IGHV1-69 L452-contacting antibodies are enriched in convalescents experienced Omicron BA.1 (without L452R) breakthrough infections but rarely found in Delta (with L452R) breakthrough infections. Taken together, these findings support that IGHV1-69 population antibodies contribute to selection pressure for L452 substitution. This study thus provides a better understanding of SARS-CoV-2 variant genesis and immune evasion.

COVID-19 Diagnostic Methods and Detection Techniques

Coronavirus disease 2019 (COVID-19) is an emerging human-to-human infectious disease that broke out in early December 2019 and threatens global public health, causing widespread concern. This respiratory disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The development of rapid and reliable techniques for COVID-19 diagnosis is a significant step to prevent further infections. Combinations of genome sequencing, nucleic acid molecular testing, clustered regularly interspaced short palindromic repeats editing technology, antigen/antibody detection, and computed tomography imaging have been implemented to identify and screen COVID-19 infections. Moreover, other new diagnosis methods such as dried blood spots and biosensors are being developed and are summarized here. This manuscript reviews currently available methods for SARS-CoV-2 detection with the aim of helping researchers develop timely and effective technologies to detect this emerging virus and its variants.

SARS-CoV-2 Delta and Omicron variants evade population antibody response by mutations in a single spike epitope.

Population antibody response is thought to be important in selection of virus variants. We report that SARS-CoV-2 infection elicits a population immune response that is mediated by a lineage of VH1-69 germline antibodies. A representative antibody R1-32 from this lineage was isolated. By cryo-EM, we show that it targets a semi-cryptic epitope in the spike receptor-binding domain. Binding to this non-ACE2 competing epitope results in spike destruction, thereby inhibiting virus entry. On the basis of epitope location, neutralization mechanism and analysis of antibody binding to spike variants, we propose that recurrent substitutions at 452 and 490 are associated with immune evasion of the identified population antibody response. These substitutions, including L452R (present in the Delta variant), disrupt interactions mediated by the VH1-69-specific hydrophobic HCDR2 to impair antibody-antigen association, enabling variants to escape. The first Omicron variants were sensitive to antibody R1-32 but subvariants that harbour L452R quickly emerged and spread. Our results provide insights into how SARS-CoV-2 variants emerge and evade host immune responses.

Disinfection effect of hexadecyl pyridinium chloride on SARS-CoV-2 in vitro.

The novel coronavirus (COVID-19 or 2019-nCoV) is a respiratory virus that can exist in the mouth and saliva of patients and spreads through aerosol dispersion. Therefore, stomatological hospitals and departments have become high-infection-risk environments. Accordingly, oral disinfectants that can effectively inactivate the virus have become a highly active area of research. Hexadecyl pyridinium chloride, povidone-iodine, and other common oral disinfectants are the natural primary choices for stomatological hospitals. Therefore, this study investigated the inhibitory effect of hexadecyl pyridinium chloride on SARS-CoV-2 in vitro. Vero cells infected with SARS-CoV-2 were used to determine the disinfection effect; the CCK-8 method was used to determine cytotoxicity, and viral load was determined by real-time PCR. The results showed that hexadecyl pyridinium chloride has no obvious cytotoxic effect on Vero cells in the concentration range 0.0125-0.05 mg/mL. The in vitro experiments showed that hexadecyl pyridinium chloride significantly inhibits the virus at concentrations of 0.1 mg/mL or above at 2 min of action. Thus, the results provide experimental support for the use of hexadecyl pyridinium chloride in stomatological hospitals.

Immunogenicity and immune-persistence of the CoronaVac or Covilo inactivated COVID-19 Vaccine: a 6-month population-based cohort study.

Background: Owing to the coronavirus disease 2019 (COVID-19) pandemic and the emergency use of different types of COVID-19 vaccines, there is an urgent need to consider the effectiveness and persistence of different COVID-19 vaccines. Methods: We investigated the immunogenicity of CoronaVac and Covilo, two inactivated vaccines against COVID-19 that each contain inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The levels of neutralizing antibodies to live SARS-CoV-2 and the inhibition rates of neutralizing antibodies to pseudovirus, as well as the immunoglobulin (Ig)G and IgM responses towards the spike (S) and nucleocapsid (N) protein of SARS-CoV-2 at 180 days after two-dose vaccination were detected. Results: The CoronaVac and Covilo vaccines induced similar antibody responses. Regarding neutralizing antibodies to live SARS-CoV-2, 77.9% of the CoronaVac vaccine recipients and 78.3% of the Covilo vaccine recipients (aged 18-59 years) seroconverted by 28 days after the second vaccine dose. Regarding SARS-CoV-2-specific antibodies, 97.1% of the CoronaVac vaccine recipients and 95.7% of the Covilo vaccine recipients seroconverted by 28 days after the second vaccine dose. The inhibition rates of neutralizing antibody against a pseudovirus of the SARS-CoV-2 Delta variant were significantly lower compared with those against a pseudovirus of wildtype SARS-CoV-2. Associated with participant characteristics and antibody levels, persons in the older age group and with basic disease, especially a chronic respiratory disease, tended to have lower anti-SARS-CoV-2 antibody seroconversion rates. Conclusion: Antibodies that were elicited by these two inactivated COVID-19 vaccines appeared to wane following their peak after the second vaccine dose, but they persisted at detectable levels through 6 months after the second vaccine dose, and the effectiveness of these antibodies against the Delta variant of SARS-CoV-2 was lower than their effectiveness against wildtype SARS-CoV-2, which suggests that attention must be paid to the protective effectiveness, and its persistence, of COVID-19 vaccines on SARS-CoV-2 variants.

Relationship among Child Maltreatment, Parental Conflict, and Mental Health of Children during the COVID-19 Lockdown in China.

Children are more likely to experience maltreatment and parental conflict in a pandemic context, which can exacerbate their vulnerability to psychological disorders. The purpose of the present study was to examine mental health symptoms in children aged 0 to 10 years and consider related factors from the perspectives of maltreatment and parental conflict during the COVID-19 lockdown. Participants were 1286 parents aged 18 years and over with children aged 0 to 10 years were included. Several multivariable linear regressions were used to analyze the data. The largest variance in child mental health was explained by child maltreatment, as more maltreatment predicted higher reported psychological problems (standardized beta = 0.49, P < 0.001). Comparatively, parental conflict predicted less variance in mental health problems than maltreatment (standardized beta = 0.18, P < 0.001). Children who experienced more maltreatment experience and exposure to COVID-19 showed elevated levels of mental health symptoms (standardized beta = 0.06, p < 0.05), as did those who experienced parental conflict and pandemic exposure (standardized beta = 0.06, p < 0.05). The findings highlight that tailored programs that focus on a healthy family environment and strategic parental support services may be particularly effective in reducing children's mental health problems due to COVID-19 exposure.