High performance of the automated ADVIA Centaur Systems SARS-CoV-2 Antigen Assay in nasopharyngeal samples with high viral load.

ADVIA Centaur SARS-CoV-2 Antigen (COV2Ag) Assay (Siemens Healthineers) was evaluated for SARS-CoV-2 detection. A total of 141 nasopharyngeal samples were analyzed by this technique and results were compared with those obtained by quantitative reverse-transcription polymerase chain reaction (RT-PCR). The overall sensitivity and specificity of the test were 68.70% and 70%, respectively. Regarding cycle threshold (Ct) values, the COV2Ag test showed a sensitivity of 93.75% and 100% for nasopharyngeal samples with Ct < 25 and < 20, respectively. ADVIA Centaur COV2Ag Assay is a useful, automated, and rapid technique for early SARS-CoV-2 diagnosis and isolation of the infected individuals, avoiding its transmission.

Usefulness of SARS-CoV-2 antigen test sample as input for SARS-CoV-2 RT-PCR analysis.

SARS-CoV-2 rapid detection is of great interest to prevent viral dissemination. In that sense, antigen tests appeared as a very valuable tool to reach this goal. However, it is possible to obtain a negative result in those patients with low viral loads, and consequently, reverse transcription-polymerase chain reaction (RT-PCR) should be performed on samples from patients with a negative antigen test in which there is a strong suspicion of COVID infection. The common diagnostic algorithm involves taking a second sample for RT-PCR testing. This study evaluates the usefulness of the antigen test sample for carrying out RT-PCR analysis when necessary. Results obtained indicate that can be used a unique sample for both antigen test and RT-PCR. This data showed that it is possible to reduce excessive suspected individuals managing and so on increase staff security and patient comfort.

Detecting SARS-CoV-2 RNA in conjunctival secretions: Is it a valuable diagnostic method of COVID-19?

The main purpose of this study is to evaluate the presence of viral RNA of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in conjunctival swab specimen of coronavirus disease 2019 (COVID-19) patients with and without conjunctivitis to establish the diagnostic value of reverse transcription-polymerase chain reaction (RT-PCR) in each case and to describe its clinical characteristics. A cross-sectional study was conducted at the Hospital Clinico San Carlos of Madrid, Spain. Thirty-six subjects from the COVID admission unit with laboratory-confirmed SARS-CoV-2 infection were included. Conjunctival swabs were collected from 18 patients with conjunctivitis and 18 patients without conjunctivitis and RT-PCR was performed. Conjunctival swab was collected from both eyes of 36 patients (72 eyes), detecting SARS-CoV-2 RNA in conjunctival swab of two patients (5.5%). Among the 18 patients with conjunctivitis, only one of them (5.5%) showed positive results. Likewise, SARS-CoV-2 RNA was detected in one patient without conjunctivitis (5.5%). The mean age of the 36 patients was 67.9 years (range, 28-92 years) and the male-to-female ratio was 0.44 (16:20). The mean days since the onset of COVID-19 symptoms until conjunctivitis manifestation was 8 (range, 1-24 days). The mean duration of the conjunctivitis was 3 days (range, 1-7 days). SARS-CoV-2 RNA may be detected in conjunctival swabs of both patients with and without conjunctivitis. This study revealed the same rate of positive results amongst the group with and without conjunctivitis, suggesting that detecting SARS-CoV-2 in ocular fluids is not conditioned on the presence of conjunctivitis. The presence of SARS-CoV-2 RNA in ocular samples highlights the role of the eye as a possible route of transmission of the disease.

Prevalence of submicroscopic malaria infection in immigrants living in Spain.

BACKGROUND: The importance of submicroscopic malaria infections in high-transmission areas could contribute to maintain the parasite cycle. Regarding non-endemic areas, its importance remains barely understood because parasitaemia in these afebrile patients is usually below the detection limits for microscopy, hence molecular techniques are often needed for its diagnosis. In addition to this, the lack of standardized protocols for the screening of submicroscopic malaria in immigrants from endemic areas may underestimate the infection with Plasmodium spp. The aim of this study was to assess the prevalence of submicroscopic malaria in afebrile immigrants living in a non-endemic area. METHODS: A prospective, observational, multicentre study was conducted. Afebrile immigrants were included, microscopic observation of Giemsa-stained thin and thick blood smears, and two different molecular techniques detecting Plasmodium spp. were performed. Patients with submicroscopic malaria were defined as patients with negative blood smears and detection of DNA of Plasmodium spp. with one or both molecular techniques. Demographic, clinical, analytical and microbiological features were recorded and univariate analysis by subgroups was carried out with STATA v15. RESULTS: A total of 244 afebrile immigrants were included in the study. Of them, 14 had a submicroscopic malaria infection, yielding a prevalence of 5.7% (95% confidence interval 3.45-9.40). In 71.4% of the positive PCR/negative microscopy cases, Plasmodium falciparum alone was the main detected species (10 out of the 14 patients) and in 4 cases (28.6%) Plasmodium vivax or Plasmodium ovale were detected. One patient had a mixed infection including three different species. CONCLUSIONS: The prevalence of submicroscopic malaria in afebrile immigrants was similar to that previously described in Spain. Plasmodium vivax and P. ovale were detected in almost a third of the submicroscopic infections. Screening protocols for afebrile immigrants with molecular techniques could be useful for a proper management of these patients.

Probiotic Yogurt for the Prevention of Antibiotic-associated Diarrhea in Adults: A Randomized Double-blind Placebo-controlled Trial.

GOAL: To evaluate the effect of yogurt supplemented with probiotic bacteria on the prevention of antibiotic-associated diarrhea (AAD) in hospitalized patients. BACKGROUND: Diarrhea following antibiotic administration is a frequent clinical problem. The usefulness of probiotics for the prevention of AAD in the hospitalized adult population remains unclear. STUDY: A randomized, double-blind, placebo-controlled clinical trial was conducted in hospitalized patients who started antibiotic treatment. Patients were randomized (2:2:1) to receive a daily amount of 200 mL of placebo-yogurt (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus), 200 mL of probiotic yogurt (previous plus Lactobacillus acidophilus La-5, Bifidobacterium animalis subsp. lactis Bb-12 and Lactobacillus casei subsp. casei Lc-01 or no yogurt (unblinded control) within 48 hours of beginning the antibiotic therapy and up to 5 days after stopping the antibiotic. Patients were followed up with for 1 month to determine occurrence of diarrhea. RESULTS: We included 314 patients, mean age 76 years. The rate of diarrhea was 23.0% in the probiotic group versus 17.6% in the placebo group, absolute risk reduction -5.35% (95% confidence interval, -15.4% to 4.7%; P=0.30). Rate of diarrhea was similar in the unblinded external control and in the blinded study groups combined (20.9% vs. 20.2% respectively; P=0.91). There was no difference in the duration of diarrhea, maximum number of bowel movements or prolonged admission because of diarrhea among the groups. All-cause mortality did not differ between groups. CONCLUSIONS: The combined probiotic strains LA-5, BB-12, and LC-01 do not have an effect in the prevention of AAD in hospitalized patients.

The contribution of telemedicine to hepatitis C elimination in a correctional facility.

BACKGROUND: micro-elimination has been recently proposed as an efficient strategy to achieve global hepatitis C virus (HCV) elimination. The Spanish Health Ministry Strategic Plan for hepatitis C infection highlighted intervention in prisons as a priority action. However, there are important barriers associated with the specialized care provision to the penitentiary population. AIMS: to assess the contribution of telemedicine for HCV elimination in a correctional facility in Spain. METHODS: an open label program of HCV elimination via telemedicine was started on February 3rd, 2015 in a large penitentiary of 1,200 inmates, as an alternative to referring patients to specialists. An anonymous satisfaction survey was performed among a random sample of inmates and all participating doctors. RESULTS: the prevalence of HCV viremia prior to program initiation was 12.4%. One hundred and thirty-one patients received DAA HCV treatment during the period 2015-2018; 42.74% had a HCV-HIV co-infection. Overall, 97% achieved a sustained virological response (SVR). A second regime of DAA successfully rescued non-responder patients and the HCV prevalence was zero at the end of the program. Satisfaction was high or very high according to 67% of inmates and all participating doctors. CONCLUSION: telemedicine is an effective tool for HCV elimination in penitentiary correctional facilities where referral to specialists is difficult. The extensive use of this technology should be recommended in this setting in order to facilitate equitable access to specialized care.

Successful treatment of multidrug-resistant Pseudomonas aeruginosa breakthrough bacteremia with ceftolozane/tazobactam.

INTRODUCTION: Ceftolozane/tazobactam is a novel antibiotic approved for the treatment of complicated intra-abdominal and complicated urinary tract infections. CASE DESCRIPTION: We describe the use of off-label ceftolozane/tazobactam in the management of a multidrug-resistant Pseudomonas aeruginosa bacteremia that was already being treated with colistin and amikacin, the only active antibiotics according to the antibiogram.

Health-care management of an unexpected case of Ebola virus disease at the Alcorcón Foundation University Teaching Hospital.

INTRODUCTION: The first Ebola virus infected patient outside Africa was diagnosed and treated at Alcorcón Foundation University Teaching Hospital (AFUTH). We describe the integrated management strategy (medical, occupational health, preventive and public health) applied to the case. METHODS: Descriptive study of health-care management of an unexpected case of Ebola virus disease (EVD) at AFUTH treated on 6 October 2014. We describe the clinical evolution of the patient while he was attended at the Emergency Department, the drawing-up process of the action protocol, the process of training of hospital staff, the administrative management for transferring the patient to the referral centre, and the measures implemented for cleaning, disinfection and management of waste. Qualitative variables are expressed as percentages. RESULTS: Our centre designed and updated, from May to October, five versions of the acting and care protocol for patients with EVD. The protocol was in force at the AFUTH when a nursing assistant was attended on 6 October 2014. All preventive, diagnostic and therapeutic measures outlined in the protocol were applied and 206 professionals had received training and information about care procedures with a suspect case. CONCLUSION: Health-care management of an unexpected case of EVD was adequate and there was no secondary cases in our staff as a result. All resources available should be used to fight EVD.

Comparison of imported Plasmodium ovale curtisi and P. ovale wallikeri infections among patients in Spain, 2005-2011.

Sequencing data from Plasmodium ovale genotypes co-circulating in multiple countries support the hypothesis that P. ovale curtisi and P. ovale wallikeri are 2 separate species. We conducted a multicenter, retrospective, comparative study in Spain of 21 patients who had imported P. ovale curtisi infections and 14 who had imported P. ovale wallikeri infections confirmed by PCR and gene sequencing during June 2005-December 2011. The only significant finding was more severe thrombocytopenia among patients with P. ovale wallikeri infection than among those with P. ovale curtisi infection (p = 0.031). However, we also found nonsignificant trends showing that patients with P. ovale wallikeri infection had shorter time from arrival in Spain to onset of symptoms, lower level of albumin, higher median maximum core temperature, and more markers of hemolysis than did those with P. ovale curtisi infection. Larger, prospective studies are needed to confirm these findings.

Cell immunity to SARS-CoV-2 after natural infection and/or different vaccination regimens.

Background: The aim of the study was to evaluate the humoral and cellular immunity after SARS-CoV-2 infection and/or vaccination according to the type of vaccine, number of doses and combination of vaccines. Methods: Volunteer subjects were sampled between September 2021 and July 2022 in Hospital Clínico San Carlos, Madrid (Spain). Participants had different immunological status against SARS-CoV-2: vaccinated and unvaccinated, with or without previous COVID-19 infection, including healthy and immunocompromised individuals. Determination of IgG against the spike protein S1 subunit receptor-binding domain (RBD) was performed by chemiluminescence microparticle immunoassay (CMIA) using the Architect i10000sr platform (Abbott). The SARS-CoV-2-specific T-cell responses were assessed by quantification of interferon gamma release using QuantiFERON SARS-CoV-2 assay (Qiagen). Results: A total of 181 samples were collected, 170 were from vaccinated individuals and 11 from unvaccinated. Among the participants, 41 were aware of having previously been infected by SARS-CoV-2. Vaccinated people received one or two doses of the following vaccines against SARS-CoV-2: ChAdOx1-S (University of Oxford-AstraZeneca) (AZ) and/orBNT162b2 (Pfizer-BioNTech)(PZ). Subjects immunized with a third-booster dose received PZ or mRNA-1273 (Moderna-NIAID)(MD) vaccines. All vaccinees developed a positive humoral response (>7.1 BAU/ml), but the cellular response varied depending on the vaccination regimen. Only AZ/PZ combination and 3 doses of vaccination elicited a positive cellular response (median concentration of IFN- γ > 0.3 IU/ml). Regarding a two-dose vaccination regimen, AZ/PZ combination induced the highest humoral and cellular immunity. A booster with mRNA vaccine resulted in increases in median levels of IgG-Spike antibodies and IFN-γ as compared to those of two-dose of any vaccine. Humoral and cellular immunity levels were significantly higher in participants with previous infection compared to those without infection. Conclusion: Heterologous vaccination (AZ/PZ) elicited the strongest immunity among the two-dose vaccination regimens. The immunity offered by the third-booster dose of SARS-CoV-2 vaccine depends not only on the type of vaccine administered but also on previous doses and prior infection. Previous exposure to SARS-CoV-2 antigens by infection strongly affect immunity of vaccinated individuals.

Respiratory syncytial virus infection in adults: Differences with influenza.

INTRODUCTION: Respiratory syncytial virus (RSV) causes an acute respiratory illness similar to influenza, although there are few data comparing both of them in adults. The existence of clinical differences between these two infections could have implications for their management. MATERIALS AND METHODS: Retrospective observational cohort study including 63 adults with positive PCR for RSV and 221 for influenza during winter 2018-2019. Epidemiological, clinical characteristics and outcomes were contrasted between both groups. RESULTS: Compared to influenza, RSV-positive patients presented a higher association with active neoplasia (OR=2.9; 95% CI: 1.2-6.9), dependence for basic activities of daily living (OR=3.4; 95% CI: 1.4-8.2) and immunosuppression due to chronic glucocorticoid administration (OR=7.6; 95% CI: 1.6-36.1). At diagnosis, fever was less common (OR=0.3; 95% CI: 0.2-0.7), and C-reactive protein level ≥100mg/l was more frequent (OR=2.1; 95% CI: 1.0-4.5). They developed bacterial co-infection by Staphylococcus aureus in a higher proportion (OR=8.3; 95% CI: 1.5-46.9) and presented a greater need for admission to the intensive care unit (OR=5.4; 95% CI: 1.4-19.2). CONCLUSION: RSV is an important cause of respiratory illness in adults during the influenza season. It especially affects vulnerable patients with chronic underlying diseases, and has a higher morbidity than influenza. For all these reasons, specific detection, prevention and treatment of RSV is necessary in order to reduce the consumption of health care resources due to RSV disease in adults.

Incidence of sexually transmitted infections and screening models among pre-exposure prophylaxis users.

INTRODUCTION: There is discussion about the frequency of STI screening among pre-exposure prophylaxis (PrEP) users. The aim of this study was to analyse the incidence of STIs and to evaluate different screening models in order to optimise the follow-up. METHODOLOGY: A prospective study was conducted between 2017 and 2023, including 138 PrEP users in a STI clinic. Participants were tested for STIs every three months. Unscheduled visits were performed for those with STI-related symptoms or for people who were notified for an STI by a sexual partner. We performed a survival analysis of repeated events, estimating the cumulative incidence (CI) and incidence rate (IR). RESULTS: The overall CI by quarterly screening was 8.3 (95% CI: 7.6-9.1) infections per person over six years, with a decreasing trend. The most frequently diagnosed pathogen was Neisseria gonorrhoeae, with a IR of 0.76 (95% CI: 0.68-0.84). If the frequency of screening is reduced to every six months, the IR of STIs is reduced by (95% CI: 0.5-0.66) infections per user per year, and at 12 months by 0.82 (95% CI: 0.73-0.89). In the case of no pharyngeal or urethral screening, IR is reduced by 0.37 (95% CI: 0.32-0.42) infections per person per year and in those over 35 years of age by 0.33 (95% CI: 0.25-0.4). Eliminating unscheduled visits, the reduction in IR is 0.33 (95% CI: 0.24-0.42). CONCLUSIONS: The incidence of STIs among PrEP users is high, especially in the rectum, but it does not increase over time. STI screening could be optimised reducing the frequency of pharyngeal and urethral testing, particularly in those over 35 years of age. It is essential to redistribute health resources for unscheduled visits, which have been shown to be the most cost-effective screening.

Monkeypox virus genomic accordion strategies.

The 2023 monkeypox (mpox) epidemic was caused by a subclade IIb descendant of a monkeypox virus (MPXV) lineage traced back to Nigeria in 1971. Person-to-person transmission appears higher than for clade I or subclade IIa MPXV, possibly caused by genomic changes in subclade IIb MPXV. Key genomic changes could occur in the genome's low-complexity regions (LCRs), which are challenging to sequence and are often dismissed as uninformative. Here, using a combination of highly sensitive techniques, we determine a high-quality MPXV genome sequence of a representative of the current epidemic with LCRs resolved at unprecedented accuracy. This reveals significant variation in short tandem repeats within LCRs. We demonstrate that LCR entropy in the MPXV genome is significantly higher than that of single-nucleotide polymorphisms (SNPs) and that LCRs are not randomly distributed. In silico analyses indicate that expression, translation, stability, or function of MPXV orthologous poxvirus genes (OPGs), including OPG153, OPG204, and OPG208, could be affected in a manner consistent with the established "genomic accordion" evolutionary strategies of orthopoxviruses. We posit that genomic studies focusing on phenotypic MPXV differences should consider LCR variability.

Emergence of OXA-48-producing Klebsiella pneumoniae and the novel carbapenemases OXA-244 and OXA-245 in Spain.

OBJECTIVES: To describe the molecular and population-level characterization of a selected group of OXA-48-like-producing Klebsiella pneumoniae isolates collected in Spain between January 2011 and May 2012. METHODS: During the study period, 151 OXA-48-like-producing K. pneumoniae isolates were collected from 10 hospitals in six different Spanish regions. From these, a representative sample of 21 isolates that caused hospital outbreaks and single infections was selected for further in-depth analysis. Molecular epidemiology was investigated using PFGE and multilocus sequence typing (MLST). Resistance genes were characterized by PCR and sequencing. Plasmids carrying bla(OXA-48-like) were studied by PFGE with S1 nuclease digestion. RESULTS: All 21 isolates had ertapenem MICs ≥ 1 mg/L, but 47.6% remained susceptible to imipenem and meropenem; bla(OXA-48) was identified in 19 isolates (90.5%) and the novel bla(OXA-244) and bla(OXA-245) genes were detected in 1 isolate each. With one exception, all isolates that contained bla(OXA-48-like) also contained bla(CTX-M-15). PFGE typing revealed six clusters comprising isolates that belonged to MLST types ST11, ST16, ST392, ST405, ST437 and ST663, respectively. Two main clusters were identified: PFGE cluster 1 (12 isolates, belonging either to ST405 or ST663, from seven hospitals), and PFGE cluster 2 (4 ST16 isolates from two hospitals). Six of seven donor isolates conjugated successfully; bla(OXA-48-like) (but not bla(CTX-M-15)) was carried on ≈ 60 kb Inc L/M plasmids. CONCLUSIONS: Multidrug-resistant K. pneumoniae producing OXA-48-like carbapenemase are emerging as important pathogens in Spain due to intra- and inter-hospital, clonal and non-clonal dissemination.

Evolution of antibody titers after two doses of mRNA Pfizer-BioNTech vaccine and effect of the third dose in nursing home residents.

OBJECTIVES: We evaluated the IgG antibody titer against SARS-CoV-2 in 196 residents of a Spanish nursing home after the second dose of the BNT162b2 vaccine and the evolution of this titer over time. The role of the third dose of the vaccine on immune-response is also analysed in 115 of participants. METHODS: Vaccine response was evaluated 1, 3 and 6 months after second dose of Pfizer-BioNTech COVID-19 Vaccine and 30 days after booster vaccination. Total anti-RBD (receptor binding domain) IgG immunoglobulins were measured to assess response. Six month after the second dose of vaccine and previously to the booster, T-cell response was also measured in 24 resident with different antibody levels. T-spot Discovery SARS-CoV-2 kit was used to identify cellular immunogenicity. RESULTS: As high as 99% of residents demonstrated a positive serological response after second dose. Only two patients showed no serologic response, two men without records of previous SARS-CoV-2 infection. A higher immune response was associated with prior SARS-CoV-2 infection regardless of the gender or age. The anti-S IgG titers decreased significantly in almost all the participants (98.5%) after six months of vaccination whatever previous COVID-infection. The third dose of vaccine increased antibody titers in all patients, although initial vaccination values were not restored in the majority of cases. CONCLUSION: The main conclusion of the study is that vaccine resulted in good immunogenicity in this vulnerable population. Nevertheless more data are needed on the long-term maintenance of antibody response after booster vaccination.

Carbapenemase-Producing Klebsiella pneumoniae in COVID-19 Intensive Care Patients: Identification of IncL-VIM-1 Plasmid in Previously Non-Predominant Sequence Types.

During the COVID-19 pandemic, intensive care units (ICUs) operated at or above capacity, and the number of ICU patients coinfected by nosocomial microorganisms increased. Here, we characterize the population structure and resistance mechanisms of carbapenemase-producing Klebsiella pneumoniae (CP-Kpn) from COVID-19 ICU patients and compare them to pre-pandemic populations of CP-Kpn. We analyzed 84 CP-Kpn isolates obtained during the pandemic and 74 CP-Kpn isolates obtained during the pre-pandemic period (2019) by whole genome sequencing, core genome multilocus sequence typing, plasmid reconstruction, and antibiotic susceptibility tests. More CP-Kpn COVID-19 isolates produced OXA-48 (60/84, 71.4%) and VIM-1 (18/84, 21.4%) than KPC (8/84, 9.5%). Fewer pre-pandemic CP-Kpn isolates produced VIM-1 (7/74, 9.5%). Cefiderocol (97.3-100%) and plazomicin (97.5-100%) had the highest antibiotic activity against pandemic and pre-pandemic isolates. Sequence type 307 (ST307) was the most widely distributed ST in both groups. VIM-1-producing isolates belonging to ST307, ST17, ST321 and ST485, (STs infrequently associated to VIM-1) were detected during the COVID-19 period. Class 1 integron Int1-blaVIM-1-aac(6')-1b-dfrB1-aadAI-catB2-qacEΔ1/sul1, found on an IncL plasmid of approximately 70,000 bp, carried blaVIM-1 in ST307, ST17, ST485, and ST321 isolates. Thus, CP-Kpn populations from pandemic and pre-pandemic periods have similarities. However, VIM-1 isolates associated with atypical STs increased during the pandemic, which warrants additional monitoring and surveillance.

Specific Cellular and Humoral Immune Responses to the Neoantigen RBD of SARS-CoV-2 in Patients with Primary and Secondary Immunodeficiency and Healthy Donors.

Patients with antibody deficiency disorders, such as primary immunodeficiency (PID) or secondary immunodeficiency (SID) to B-cell lymphoproliferative disorder (B-CLPD), are two groups vulnerable to developing the severe or chronic form of coronavirus disease caused by SARS-CoV-2 (COVID-19). The data on adaptive immune responses against SARS-CoV-2 are well described in healthy donors, but still limited in patients with antibody deficiency of a different cause. Herein, we analyzed spike-specific IFN-γ and anti-spike IgG antibody responses at 3 to 6 months after exposure to SARS-CoV-2 derived from vaccination and/or infection in two cohorts of immunodeficient patients (PID vs. SID) compared to healthy controls (HCs). Pre-vaccine anti-SARS-CoV-2 cellular responses before vaccine administration were measured in 10 PID patients. Baseline cellular responses were detectable in 4 out of 10 PID patients who had COVID-19 prior to vaccination, perceiving an increase in cellular responses after two-dose vaccination (p < 0.001). Adequate specific cellular responses were observed in 18 out of 20 (90%) PID patients, in 14 out of 20 (70%) SID patients and in 74 out of 81 (96%) HCs after vaccination (and natural infection in some cases). Specific IFN-γ response was significantly higher in HC with respect to PID (1908.5 mUI/mL vs. 1694.1 mUI/mL; p = 0.005). Whereas all SID and HC patients mounted a specific humoral immune response, only 80% of PID patients showed positive anti-SARS-CoV-2 IgG. The titer of anti-SARS-CoV-2 IgG was significantly lower in SID compared with HC patients (p = 0.040), without significant differences between PID and HC patients (p = 0.123) and between PID and SID patients (p =0.683). High proportions of PID and SID patients showed adequate specific cellular responses to receptor binding domain (RBD) neoantigen, with a divergence between the two arms of the adaptive immune response in PID and SID patients. We also focused on the correlation of protection of positive SARS-CoV-2 cellular response to omicron exposure: 27 out of 81 (33.3%) HCs referred COVID-19 detected by PCR or antigen test, 24 with a mild course, 1 with moderate symptoms and the remaining 2 with bilateral pneumonia that were treated in an outpatient basis. Our results might support the relevance of these immunological studies to determine the correlation of protection with severe disease and for deciding the need for additional boosters on a personalized basis. Follow-up studies are required to evaluate the duration and variability in the immune response to COVID-19 vaccination or infection.

Analysis of Adverse Effects of COVID-19 Vaccines in Spain following Booster Dose.

The present study evaluates the adverse effects of three vaccines: AstraZeneca (Vaxzevria), Pfizer/BioNTech (Comirnaty) and Moderna (Spikevax) according to the dose. From 733 participants collected, the vaccine schedule was as follows: 330 (45%) received a double dose of the AstraZeneca vaccine, 382 (52.1%) received a double dose of Pfizer, 18 (2.5%) received a heterologous prime boost and 3 (0.4%) received a single dose. Pfizer and Moderna vaccines were administered as a third dose in 70 and 121 individuals, respectively. Local and systemic reactions observed in the three vaccines were mild to moderate in severity. Only one AstraZeneca recipient (0.3%) presented a serious adverse effect: blurred vision. Adverse events were more frequent after the first dose of AstraZeneca and after the second dose of Pfizer. As the third dose, Moderna causes more adverse effects than Pfizer regardless of the type of vaccine previously administered, whereas the reactogenicity of a third dose of Pfizer is slightly higher in the group previously vaccinated with Pfizer than in that group with AstraZeneca. In short, secondary effects of the third dose of COVID-19 vaccines were similar to those after dose 2, but their frequency depends on the type of vaccine and the combinations of vaccines.

A Prospective Study of the Serological, Clinical, and Epidemiological Features of a SARS-CoV-2 Positive Pediatric Cohort.

Background: SARS-CoV-2 was a global pandemic. Children develop a mild disease and may have a different rate of seroconversion compared to adults. The objective was to determine the number of seronegative patients in a pediatric cohort. We also reviewed the clinical−epidemiological features associated with seroconversion. Methods: A multicenter prospective observational study during September−November 2020, of COVID-19, confirmed by reverse transcription-polymerase chain reaction. Data were obtained 4−8 weeks after diagnosis. Blood samples were collected to investigate the humoral response, using three different serological methods. Results: A total of 111 patients were included (98 symptomatic), 8 were admitted to hospital, none required an Intensive Care Unit visit. Median age: 88 months (IQR: 24−149). Median time between diagnosis and serological test: 37 days (IQR: 34−44). A total of 19 patients were non-seroconverters when using three serological techniques (17.1%; 95% CI: 10.6−25.4); most were aged 2−10 years (35%, p < 0.05). Univariate analysis yielded a lower rate of seroconversion when COVID-19 confirmation was not present amongst household contacts (51.7%; p < 0.05). Conclusions: There was a high proportion of non-seroconverters. This is more commonly encountered in childhood than in adults. Most seronegative patients were in the group aged 2−10 years, and when COVID-19 was not documented in household contacts. Most developed a mild disease. Frequently, children were not the index case within the family.

Seroprevalence of anti-SARS-CoV-2 IgG antibodies: relationship with COVID-19 diagnosis, symptoms, smoking, and method of transmission.

Aims: The study of SARS-CoV-2 antibodies in the population is a crucial step towards overcoming the COVID-19 pandemic. Seroepidemiological studies allow an estimation of the number of people who have been exposed to the virus, as well as the number of people who are still susceptible to infection. Methods: In total, 13 560 people from Arganda del Rey, Madrid (Spain) were assessed between January and March 2021 for the presence of IgG antibodies, using rapid tests and histories of symptoms compatible with COVID-19. Results: 24.2% of the participants had IgG antibodies and 9% had a positive COVID-19 diagnosis. Loss of smell/taste was the most discriminating symptom of the disease. The main transmitters of infection were found to be household members. Unexpectedly, in smokers, the incidence of positive COVID-19 diagnoses was significantly lower. Additionally, it was found that there was a discrepancy between COVID-19 diagnosis and the presence of IgG antibodies. Conclusions: Rapid anti-IgG tests are less reliable in detecting SARS-CoV-2 infection at an individual level, but are functional in estimating SARS-CoV-2 infection rates at an epidemiological level. The loss of smell/taste is a potential indicator for establishing COVID-19 infection.