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1.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-308828

ABSTRACT

BACKGROUND: Despite SARS-CoV-2 immunizations have started in most countries, children are not currently included in the vaccination programs, thus it remains crucial to define their anti-SARS-CoV-2 immune response in order to minimize the risk for other epidemic waves. This study seeks to provide a description of the virology ad anti-SARS-CoV-2 immunity in children with distinct symptomatology. METHODS: Between March and July 2020, we recruited 15 SARS-CoV-2 asymptomatic (AS) and 51 symptomatic children (SY), stratified according to WHO clinical classification. We measured SARS-CoV-2 viral load using ddPCR and qPCR in longitudinally collected nasopharyngeal swabs samples. To define anti-SARS-CoV-2 antibodies we measured neutralization activity and total IgG load (Diasorin). We also evaluated antigen-specific B and CD8+T-cells, using a labelled S1+S2 protein and ICAM expression, respectively. Plasma protein profiling was performed with Olink. RESULTS: Virological profiling showed that AS had lower viral load at diagnosis (p=0.004) and faster virus clearance (p=0.0002) compared to SY. Anti-SARS CoV-2 humoral and cellular response did not appear to be associated with the presence of symptoms. AS and SY showed similar titers of SARS-CoV-2 IgG, levels of neutralizing activity, and frequency of Ag-specific B and CD8+T-cells. Whereas pro-inflammatory plasma protein profile was associated to symptomatology. CONCLUSION: We demonstrated the development of anti-SARS-CoV-2 humoral and cellular response with any regards to symptomatology, suggesting the ability of both SY and AS to contribute towards herd immunity. The virological profiling of AS suggested that they have lower virus load associated with faster virus clearance.

2.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-308827

ABSTRACT

As the global COVID-19 pandemic progresses and with the school reopening, it is paramount to gain knowledge on adaptive immunity to SARS-CoV-2 in children in order to define possible immunization strategies and reconsider pandemic control measures. We analyzed anti-SARS-CoV-2 antibodies (Ab) and their neutralizing activity (PRNT) in 42 COVID-19-infected children 7 days after symptoms onset. Individuals with specific humoral responses presented faster virus clearance, and lower viral load associated to a reduced in vitro infectivity. We demonstrated that the frequencies of SARS-CoV-2 specific CD4-CD40L+ T-cells and Spike specific B-cells were associated with the anti-SARS-CoV-2 Ab and the magnitude of neutralizing activity. The plasma proteome confirmed the association between cellular and humoral SARS-CoV-2 immunity, with PRNT+ patients showing higher viral signal transduction molecules (SLAMF1, CD244, CLEC4G). This work shed lights on cellular and humoral anti-SARS-CoV-2 responses in children which may drive future vaccination trials endpoints and quarantine measures policies.Funding: This work was made possible by support from Bambino Gesù Children’s Hospital ricerca corrente 2020 to NC and ricerca corrente 2019 to PP, by PENTA and by Fondazione Cassa di Risparmio di Padova e Rovigo, Progetti di Ricerca Covid-19 (ADR participant).Conflict of Interest: The authors declare no competing interests.Ethical Approval: Local ethical committee approved the study and written informed consent was obtained from all participants or legal guardians.

3.
Cell Host Microbe ; 30(3): 400-408.e4, 2022 03 09.
Article in English | MEDLINE | ID: covidwho-1650182

ABSTRACT

Breakthrough SARS-CoV-2 infections in fully vaccinated individuals are considered a consequence of waning immunity. Serum antibodies represent the most measurable outcome of vaccine-induced B cell memory. When antibodies decline, memory B cells are expected to persist and perform their function, preventing clinical disease. We investigated whether BNT162b2 mRNA vaccine induces durable and functional B cell memory in vivo against SARS-CoV-2 3, 6, and 9 months after the second dose in a cohort of health care workers (HCWs). While we observed physiological decline of SARS-CoV-2-specific antibodies, memory B cells persist and increase until 9 months after immunization. HCWs with breakthrough infections had no signs of waning immunity. In 3-4 days, memory B cells responded to SARS-CoV-2 infection by producing high levels of specific antibodies in the serum and anti-Spike IgA in the saliva. Antibodies to the viral nucleoprotein were produced with the slow kinetics typical of the response to a novel antigen.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Vaccination , Vaccines, Synthetic
5.
PLoS One ; 16(12): e0260947, 2021.
Article in English | MEDLINE | ID: covidwho-1556896

ABSTRACT

BACKGROUND: On 9th January 2020, China CDC reported a novel coronavirus (later named SARS-CoV-2) as the causative agent of the coronavirus disease 2019 (COVID-19). Identifying the first appearance of virus is of epidemiological importance to tracking and mapping the spread of SARS-CoV-2 in a country. We therefore conducted a retrospective observational study to detect SARS-CoV-2 in oropharyngeal samples collected from hospitalized patients with a Severe Acute Respiratory Infection (SARI) enrolled in the DRIVE (Development of Robust and Innovative Vaccine Effectiveness) study in five Italian hospitals (CIRI-IT BIVE hospitals network) (1st November 2019 - 29th February 2020). OBJECTIVES: To acquire new information on the real trend in SARS-CoV-2 infection during pandemic phase I and to determine the possible early appearance of the virus in Italy. MATERIALS AND METHODS: Samples were tested for influenza [RT-PCR assay (A/H1N1, A/H3N2, B/Yam, B/Vic)] in accordance with the DRIVE study protocol. Subsequently, swabs underwent molecular testing for SARS-COV-2. [one-step real-time multiplex retro-transcription (RT) PCR]. RESULTS: In the 1683 samples collected, no evidence of SARS-CoV-2 was found. Moreover, 28.3% (477/1683) of swabs were positive for influenza viruses, the majority being type A (358 vs 119 type B). A/H3N2 was predominant among influenza A viruses (55%); among influenza B viruses, B/Victoria was prevalent. The highest influenza incidence rate was reported in patients aged 0-17 years (40.3%) followed by those aged 18-64 years (24.4%) and ≥65 years (14.8%). CONCLUSIONS: In Italy, some studies have shown the early circulation of SARS-CoV-2 in northern regions, those most severely affected during phase I of the pandemic. In central and southern regions, by contrast no early circulation of the virus was registered. These results are in line with ours. These findings highlight the need to continue to carry out retrospective studies, in order to understand the epidemiology of the novel coronavirus, to better identify the clinical characteristics of COVID-19 in comparison with other acute respiratory illnesses (ARI), and to evaluate the real burden of COVID-19 on the healthcare system.


Subject(s)
Influenza, Human/epidemiology , Severe Acute Respiratory Syndrome/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19/virology , Female , Hospitals , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza B virus/genetics , Influenza B virus/isolation & purification , Influenza, Human/pathology , Influenza, Human/virology , Italy/epidemiology , Male , Middle Aged , RNA, Viral/genetics , RNA, Viral/metabolism , Retrospective Studies , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Severe Acute Respiratory Syndrome/pathology , Severe Acute Respiratory Syndrome/virology , Young Adult
6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296187

ABSTRACT

SARS-CoV2 is a new coronavirus which started spreading in December 2019 from Wuhan, China. The seroprevalence of SARS-CoV2 antibodies allows to define a better picture of the spread of SARS-CoV2 infection in the population. The duration of SARS-CoV2 antibodies in the healthy population as well as in immunocompromised patients is still a topic of debate. HIV-infected people are at increased risk of developing complications from contracting a viral illness. Furthermore,their ability to develop and maintain an optimal immunological response to any kind of pathogen appears to be reduced.We analyzed the overall seroprevalence of SARS-CoV2 antibodies in 85 HIV infected-people on ART aged between 5 and 34 years old from May to January 2021. 88,2%of patients were in a good state of viroimmunological control: 23 showed a VL<40cp/ml and 52 had an undetectable VL. When positive for SARS-CoV2 serology, a confirmatory nasopharyngeal swab for PCR assessment and a second serological assay would be performed.Out of the 85 patients, 5 proved to be positive for SARS-CoV2 antibodies (rate of prevalence 5.8%). In all 5 cases the nasopharyngeal swabs were negative and the second assay for SARS-CoV2 antibodies performed in 4 out of 5 patients a week later was negative as well. The anamnestic recall brought no elements of suspicion for a past infection.The duration of SARS-CoV2 antibodies after COVID19 disease is still poorly understood in healthy population and additional studies will be needed to define the durability of humoral responses in immunocompromised children and in particular in HIV infected children under effective ART. It is still unknown whether ART or their immunological impairment may in part mitigate the pathogenesis of SARS-CoV-2 infection. Also, it will be interesting to analyze the impact of vaccination against SARS-CoV2 in HIV infected patients with a satisfactory virological control.

7.
SSRN; 2021.
Preprint in English | SSRN | ID: ppcovidwho-292059

ABSTRACT

Background: Breakthrough infections in fully vaccinated HCWs are considered a marker of waning immunity. Serum antibodies represent the most visible and measurable outcome of vaccine-induced B-cell memory. When antibodies decline, memory B cells are expected to persist and perform their function, thus preventing clinical disease. We investigated whether BNT162b2 mRNA vaccine induces durable and in vivo functional B-cell memory against SARS-CoV-2 3, 6 and 9 months after the second dose. Methods: We assessed the duration of SARS-CoV-2 vaccine-induced immunity by measuring specific antibodies and memory B cells 3, 6 and 9 months after vaccination. In fully vaccinated HCWs with breakthrough SARS-CoV-2 infections, we evaluated the humoral and mucosal response of vaccine-induced memory B cells. Findings: Whereas specific serum antibodies decline, anti-Spike memory B cells continue to increase until 9 months after the last vaccine dose. HCWs with breakthrough infections had no signs of waning immunity on the day of the first positive swab. In 3-4 days, memory B cells responded to SARS-CoV-2 infection by producing high levels of specific antibodies in the serum. In the saliva, anti-Spike IgA also rapidly increased in response to the infection. Antibodies to the viral nucleoprotein were produced with the slow kinetics typical of the response to a novel antigen. Interpretation: SARS-CoV-2 specific antibodies physiologically decline months after vaccination. By contrast, memory B cells persist and increase over time. Parenteral administered vaccines do not generate mucosal immunity and serum antibodies reach mucosal sites in small amounts by transudation. In HCWs with SARS-CoV-2 breakthrough infections, memory B cells react by rapidly differentiating into antibody-producing cells and generating IgA for protection of mucosal sites.

8.
Cells ; 10(10)2021 09 26.
Article in English | MEDLINE | ID: covidwho-1438527

ABSTRACT

Specific memory B cells and antibodies are a reliable read-out of vaccine efficacy. We analysed these biomarkers after one and two doses of BNT162b2 vaccine. The second dose significantly increases the level of highly specific memory B cells and antibodies. Two months after the second dose, specific antibody levels decline, but highly specific memory B cells continue to increase, thus predicting a sustained protection from COVID-19. We show that although mucosal IgA is not induced by the vaccination, memory B cells migrate in response to inflammation and secrete IgA at mucosal sites. We show that the first vaccine dose may lead to an insufficient number of highly specific memory B cells and low concentration of serum antibodies, thus leaving vaccinees without the immune robustness needed to ensure viral elimination and herd immunity. We also clarify that the reduction of serum antibodies does not diminish the force and duration of the immune protection induced by vaccination. The vaccine does not induce sterilizing immunity. Infection after vaccination may be caused by the lack of local preventive immunity because of the absence of mucosal IgA.


Subject(s)
Antibodies, Viral/immunology , B-Lymphocytes/cytology , COVID-19 Vaccines/therapeutic use , COVID-19/immunology , COVID-19/prevention & control , Immunoglobulin A/immunology , Immunologic Memory , Adult , Antibodies, Neutralizing/blood , Antigens, Viral/immunology , B-Lymphocytes/immunology , Cryopreservation , Female , Health Personnel , Healthy Volunteers , Hospitals, Pediatric , Humans , Immunoglobulin G , Immunoglobulin M/immunology , Lactation , Male , Middle Aged , Mucous Membrane/immunology , Patient Safety , SARS-CoV-2 , Vaccination
9.
Pediatr Allergy Immunol ; 32(8): 1833-1842, 2021 11.
Article in English | MEDLINE | ID: covidwho-1282025

ABSTRACT

BACKGROUND: Although SARS-CoV-2 immunizations have started in most countries, children are not currently included in the vaccination programs; thus, it remains crucial to define their anti-SARS-CoV-2 immune response in order to minimize the risk for other epidemic waves. This study sought to provide a description of the virology ad anti-SARS-CoV-2 immunity in children with distinct symptomatology. METHODS: Between March and July 2020, we recruited 15 SARS-CoV-2 asymptomatic (AS) and 51 symptomatic (SY) children, stratified according to WHO clinical classification. We measured SARS-CoV-2 viral load using ddPCR and qPCR in longitudinally collected nasopharyngeal swab samples. To define anti-SARS-CoV-2 antibodies, we measured neutralization activity and total IgG load (DiaSorin). We also evaluated antigen-specific B and CD8+T cells, using a labeled S1+S2 protein and ICAM expression, respectively. Plasma protein profiling was performed with Olink. RESULTS: Virological profiling showed that AS patients had lower viral load at diagnosis (p = .004) and faster virus clearance (p = .0002) compared with SY patients. Anti-SARS-CoV-2 humoral and cellular response did not appear to be associated with the presence of symptoms. AS and SY patients showed similar titers of SARS-CoV-2 IgG, levels of neutralizing activity, and frequency of Ag-specific B and CD8+ T cells, whereas pro-inflammatory plasma protein profile was found to be associated with symptomatology. CONCLUSION: We demonstrated the development of anti-SARS-CoV-2 humoral and cellular response with any regard to symptomatology, suggesting the ability of both SY and AS patients to contribute toward herd immunity. The virological profiling of AS patients suggested that they have lower virus load associated with faster virus clearance.


Subject(s)
COVID-19 , Antibodies, Viral/blood , B-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Child , Humans , Immunoglobulin G/blood , SARS-CoV-2 , Serologic Tests
10.
Front Pediatr ; 9: 620598, 2021.
Article in English | MEDLINE | ID: covidwho-1247886

ABSTRACT

Background: In December 2019, a novel coronavirus named SARS-CoV-2 started circulating in China and this led to a major epidemic in Northern Italy between February and May 2020. Young children (aged <5 years) seem to be less affected by this coronavirus disease (COVID-19) compared to adults, although there is very little information on the circulation of this new virus among children in Italy. We retrospectively tested nasopharyngeal swabs for SARS-CoV-2 in samples collected in young children between November, 2019 and March, 2020 in the context of the RSV ComNet study. Methods: Two networks of primary care pediatricians in Lazio (Central Italy) and Puglia (Southern Italy) collected nasopharyngeal swabs from children, aged <5 years, presenting with symptoms for an acute respiratory infection (ARI). The RSV ComNet study is a multicenter study implemented to estimate the burden of RSV in young children (aged <5 years) in the community. Swabs were sent to a central reference laboratory and tested for 14 respiratory viruses through RT-PCR. All collected samples were retrospectively tested for SARS-CoV-2 using RT-PCR (Istituto Superiore di Sanità protocol). Results: A total of 293 children with ARI were identified in the two participating networks. The highest number of cases were recruited in weeks 51/2019 and 3/2020. The majority of patients (57%) came from the Lazio region. All of the 293 samples tested negative for SARS-Cov2. Rhinovirus was the most frequently detected virus (44%), followed by RSV (41%) and influenza viruses (14%). Conclusions: Our study shows that in Lazio (a region of intermediate SARS-COV-2 incidence) and Puglia (a region of low incidence), the SARS-Cov2 virus did not circulate in a sample of ARI pediatric cases consulting primary care pediatricians between November 2019 and March 2020.

11.
Cell Rep ; 34(11): 108852, 2021 03 16.
Article in English | MEDLINE | ID: covidwho-1135278

ABSTRACT

As the global COVID-19 pandemic progresses, it is paramount to gain knowledge on adaptive immunity to SARS-CoV-2 in children to define immune correlates of protection upon immunization or infection. We analyzed anti-SARS-CoV-2 antibodies and their neutralizing activity (PRNT) in 66 COVID-19-infected children at 7 (±2) days after symptom onset. Individuals with specific humoral responses presented faster virus clearance and lower viral load associated with a reduced in vitro infectivity. We demonstrated that the frequencies of SARS-CoV-2-specific CD4+CD40L+ T cells and Spike-specific B cells were associated with the anti-SARS-CoV-2 antibodies and the magnitude of neutralizing activity. The plasma proteome confirmed the association between cellular and humoral SARS-CoV-2 immunity, and PRNT+ patients show higher viral signal transduction molecules (SLAMF1, CD244, CLEC4G). This work sheds lights on cellular and humoral anti-SARS-CoV-2 responses in children, which may drive future vaccination trial endpoints and quarantine measures policies.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Adaptive Immunity/immunology , B-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/immunology , COVID-19/virology , Child , Humans , Immunity, Humoral/immunology , Proteome/immunology , SARS-CoV-2/immunology , Signal Transduction/immunology , Viral Load/immunology
12.
Ital J Pediatr ; 47(1): 23, 2021 Feb 02.
Article in English | MEDLINE | ID: covidwho-1061200

ABSTRACT

BACKGROUND: During the first SARS-CoV-2 pandemic phase, the sudden closure of schools was one of the main measures to minimize the spread of the virus. In the second phase, several safety procedures were implemented to avoid school closure. To evaluate if the school is a safe place, students and staff of two school complexes of Rome were monitored to evaluate the efficacy of prevention measures inside the school buildings. METHODS: Oral secretions specimens were collected from 1262 subjects for a total of 3431 samples, collected over a 3 months period. Detection of Coronavirus SARS-CoV-2 was performed by real-time PCR. Target genes were represented by E gene, RdRP/S gene and N gene. RESULTS: Among the 3431 samples analyzed, just 16 sample resulted as positive or low positive: 1 sample in the first month, 12 samples in the second month and 3 in the third month. In each period of evaluation, all positive children attended different classes. CONCLUSIONS: Even if the school has the potential for spreading viruses, our preliminary results show the efficacy of the implementations undertaken in this setting to minimize virus diffusion. Our evidence suggests that school does not act as an amplifier for transmission of SARS-CoV-2 and can be really considered a safe place for students.


Subject(s)
COVID-19/prevention & control , Disease Transmission, Infectious/prevention & control , Infection Control/methods , Pneumonia, Viral/prevention & control , School Health Services/organization & administration , Adolescent , COVID-19/epidemiology , COVID-19/transmission , COVID-19 Testing , Child , Female , Humans , Italy/epidemiology , Male , Pandemics , Pneumonia, Viral/virology , SARS-CoV-2
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