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1.
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
3.
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.

4.
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
5.
Int J Environ Res Public Health ; 18(18)2021 Sep 10.
Article in English | MEDLINE | ID: covidwho-1405459

ABSTRACT

BACKGROUND: Social distancing measures are used to reduce the spreading of COVID-19. The aim of this study was to assess the impact of local restrictions on the transmission of respiratory virus infections. METHODS: we retrospectively analyzed the nasopharyngeal samples of all patients (0-18 years old) admitted with respiratory symptoms in a large Italian tertiary hospital during the last three seasons from 2018 to 2021. RESULTS: A strong reduction in all viral respiratory infections was observed in the last season (2020-2021) compared to the two previous seasons (-79.69% and -80.66%, respectively). In particular, we found that during the epidemic period 2018-2019 and 2019-2020, the total number of Respiratory Syncytial Virus (RSV) cases was, respectively 726 and 689, while in the last season a total of five cases was detected. In the first months of 2018-2019 and 2019-2020, the total flu infections were 240 and 354, respectively, while in the last season we did not detect any influenza virus. As other viruses, the presence of Rhinovirus declined, but to a lesser extent: a total of 488 cases were assessed compared to the 1030 and 1165 cases of the two previous respective epidemic seasons. CONCLUSIONS: Public health interventions and distancing (including continuous use of face masks) settled to counter the pandemic spread of COVID-19 had a macroscopic impact on all respiratory virus transmission and related diseases, with a partial exception of Rhinovirus. The absence of viruses' circulation could result in a lack of immunity and increased susceptibility to serious infections in the next seasons.


Subject(s)
COVID-19 , Influenza, Human , Respiratory Syncytial Virus Infections , Respiratory Tract Infections , Viruses , Adolescent , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Influenza, Human/epidemiology , Pandemics , Respiratory Syncytial Virus Infections/epidemiology , Respiratory Tract Infections/epidemiology , Retrospective Studies , SARS-CoV-2 , Seasons
6.
J Med Virol ; 93(8): 5182-5187, 2021 08.
Article in English | MEDLINE | ID: covidwho-1298501

ABSTRACT

Infections due to human herpesvirus 6 (HHV-6) are frequent during early childhood. Usually, they have a favorable clinical course. Conversely, HHV-6 congenital infections occur in about 1% of neonates and may present with more severe clinical pictures. HHV-6 can be found in lung tissues and bronchoalveolar lavage (BAL) samples from patients with pneumonia and in immunocompromised patients can cause mild to severe pneumonia. In neonates, the role of HHV-6 in the genesis of severe pneumonia is poorly defined still now. We describe a healthy infant with a late-onset (15 days of life) severe interstitial pneumonia and heavy HHV-6 genome load, persistently detected in its BAL fluid. The baby underwent high-frequency oscillatory ventilation, hydroxychloroquine, steroids, and ganciclovir for 6 weeks and at 9 months she died. Next-generation sequencing of genes known to cause neonatal respiratory insufficiency revealed the presence of a "probably pathogenetic" heterozygous variant in the autosomal recessive DRC1 gene, a heterozygous variant of unknown significance (VUS) in the autosomal recessive RSPH9 gene, and a heterozygous VUS in the autosomal recessive MUC5B gene. HHV-6 infection should be considered in the differential diagnosis of late-onset severe respiratory distress in neonates and the co-occurrence of genetic predisposing factors or modifiers should be tested by specific molecular techniques. The intensity of HHV-6 genome load in BAL fluid could be an indicator of the response to antiviral therapy.


Subject(s)
Genetic Predisposition to Disease/genetics , Lung Diseases, Interstitial/genetics , Roseolovirus Infections/genetics , Cytoskeletal Proteins/genetics , Fatal Outcome , Female , Genetic Variation , Herpesvirus 6, Human/genetics , Herpesvirus 6, Human/isolation & purification , Heterozygote , Humans , Infant, Newborn , Lung Diseases, Interstitial/therapy , Lung Diseases, Interstitial/virology , Microtubule-Associated Proteins/genetics , Mucin-5B/genetics , Pneumonia, Viral/genetics , Pneumonia, Viral/therapy , Pneumonia, Viral/virology , Roseolovirus Infections/therapy , Roseolovirus Infections/virology , Viral Load
7.
Pediatr Res ; 2021 Jun 11.
Article in English | MEDLINE | ID: covidwho-1265938

ABSTRACT

BACKGROUND: The objective of this study is to test how certain signs and symptoms related to COVID-19 in children predict the positivity or negativity of the SARS-CoV-2 nasopharyngeal swab in children. METHODS: We review the data of children who were tested for SARS-CoV-2 for a suspected infection. We compared the clinical characteristics of the subjects who tested positive and negative, including the sensibility, positive and negative predictive value of different combination of signs and symptoms. RESULTS: Of all the suspected infected, 2596 tested negative (96.2%) and 103 tested positive (3.8%). The median age was 7.0 and 5.3 years for the positive and negative ones, respectively. The female to male ratio was ~1:1.3. Fever and respiratory symptoms were mostly reported. Most positive children had a prior exposure to SARS-CoV-2-infected subjects (59.2%). A total of 99.3% of patients without fever nor exposure to the virus proved negative to the SARS-CoV-2 test. CONCLUSIONS: Our study suggests that a child without fever or contact with infected subjects is SARS-CoV-2 negative. If this were to be confirmed, many resources would be spared, with improved care of both COVID-19 and not COVID-19-affected children. IMPACT: Key message: lack of fever and exposure to SARS-CoV-2-infected people highly predicts a negative results of the SARS-CoV-2 nasopharyngeal swab in the paediatric population. Added value to the current literature: this is the first article to prove this point. IMPACT: reduction of emergency department accesses of children with suspected SARS-CoV-2 infection; increased outpatient management of children with cough or other common respiratory symptoms of infancy; sparing of many human and material health resources.

9.
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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