Association of viral loads of influenza A (H3N2) with age and care setting on presentation-a prospective study during the 2022-2023 influenza season in Spain

OBJECTIVES

The aim of this study was to analyze the viral load (VL) using cycle threshold (Ct) in patients infected with influenza A (H3N2).

METHODS

This prospective study was conducted during the 2022-2023 influenza season in sentinel, non-sentinel, and hospitalized patients of Castilla y León (Spain). Respiratory samples were obtained from nasopharyngeal swabs and analyzed by quantitative reverse transcription-polymerase chain reaction specific for influenza A (H3N2) to obtain the Ct value.

RESULTS

A total of 1047 individuals were enrolled (174 [16.6%] sentinel, 200 [19.1%] non-sentinel, 673 [64.3%] hospitalized). The mean Ct value was lower in infants, young children, and in the elderly, with a sharp increase in the last from 65 years until 90 years. In addition, the lower Ct values were observed in non-sentinel patients and then in hospitalized patients, probably because non-sentinel are outpatients in the acute phase of the influenza infection.

CONCLUSIONS

A higher VL (lower Ct value) is related to the extreme ages of life: children and the elderly. Furthermore, a higher VL is related with the care setting, being probably higher in outpatients because they are in the acute phase of the disease and slightly lower in hospitalized patients because they are attended during the post-acute phase.

Factors associated to the presence of headache in patients with influenza infection and its consequences: a 2010-2020 surveillance-based study

Headache is a common symptom of influenza infection; however, its causes and consequences remain uncertain. In this manuscript, we analyzed which demographic and clinical factors were associated with the presence of headache during the course of influenza infection and whether patients with headache had a different prognosis, evaluated by need of hospitalization, sick leave or school absenteeism. The influence study (NCT05704335) was an observational study that analyzed data routinely collected from the Health Sentinel Network between 2010 and 2020. During the study period, 7832 cases were considered, among which, 5275 (67.4%) reported headache. The presence of headache was independently associated with myalgia (2.753; 95%CI: 2.456-3.087, P < 0.001), asthenia (OR: 1.958; 95%CI: 1.732-2.214, P < 0.001), shivering (OR: 1.925; 95%CI: 1.718-2.156, P < 0.001), nasopharyngeal erythema (OR: 1.505; 95%CI: 1.293-1.753, P < 0.001), fever (OR: 1.469; 95%CI: 1.159-1.861; P = 0.001), sudden onset of symptoms (OR: 1.380; 95%CI: 1.120-1.702, p = 0.004), female sex (OR: 1.134; 95%CI: 1.023-1.257, P = 0.018), and gastrointestinal symptoms (OR: 1.169; 95%CI: 1.039-1.315; P = 0.01). Patients with headache had a sex and age adjusted lower odds of being referred to the hospital (OR: 0.463; 95%CI: 0.264-0.812, P = 0.007) and a higher odd of having a sick leave and/or school absenteeism (absenteeism (OR: 1.342; 95%CI: 1.190-1.514, P < 0.001). In conclusion, the presence of headache seems associated with symptoms caused by the innate immune response. These findings support a headache pathophysiology linked with the innate immune response. Due to the potential negative consequences and its treatable nature, clinicians should systematically evaluate it and, whenever necessary, treat it too.

Impact on the time elapsed since SARS-CoV-2 infection, vaccination history, and number of doses, on protection against reinfection

SARS-CoV-2 reinfections have been frequent, even among those vaccinated. The aim of this study is to know if hybrid immunity (infection + vaccination) is affected by the moment of vaccination and number of doses received. We conducted a retrospective study in 746 patients with a history of COVID-19 reinfection and recovered the dates of infection and reinfection and vaccination status (date and number of doses). To assess differences in the time to reinfection(tRI) between unvaccinated, vaccinated before 6 months, and later; and comparing one, two or three doses (incomplete, complete and booster regime) we performed the log-rank test of the cumulative incidence calculated as 1 minus the Kaplan-Meier estimator. Also, an adjusted Cox-regression was performed to evaluate the risk of reinfection in all groups. The tRI was significantly higher in those vaccinated vs. non-vaccinated (p < 0.001). However, an early incomplete regime protects similar time than not receiving a vaccine. Vaccination before 6 months after infection showed a lower tRI compared to those vaccinated later with the same regime (adj-p < 0.001). Actually, early vaccination with complete and booster regimes provided lower length of protection compared to vaccinating later with incomplete and complete regime, respectively. Vaccination with complete and booster regimes significantly increases the tRI (adj-p < 0.001). Vaccination increases the time it takes for a person to become reinfected with SARS-CoV-2. Increasing the time from infection to vaccination increases the time in which a person could be reinfected and reduces the risk of reinfection, especially in complete and booster regimes. Those results emphasize the role of vaccines and boosters during the pandemic and can guide strategies on future vaccination policy.

InfluenCEF study: Clinical phenotype and duration of headache attributed to influenza infection

INTRODUCTION

Headache is a frequent symptom of infections. We aimed to characterize the clinical phenotype and duration of headache attributed to influenza infection.

METHODS

Prospective cohort study done in 53 primary care centers between January and April 2023. Patients were included if they had a confirmed influenza diagnosis, were older than 15 years and had a new-onset headache. Patients' demographics, prior medical history, headache phenotype and duration, associated symptoms and patients' outcomes were assessed. The International Classification of Headache Disorders criteria for headache attributed to a systemic viral infection, migraine and tension-type headache were assessed.

RESULTS

Of the 478 patients 75 fulfilled eligibility criteria. The mean age was 43, 56% were men, and 27% had a prior headache history. The headache phenotype was a bilateral headache (52%), with frontal topography (48%), pressing quality (61%), moderate intensity, rhinorrhea (79%), nasal congestion (76%), and photophobia (59%). All patients fulfilled headache attributed to acute systemic viral infection criteria, 43% fulfilled migraine criteria and 31% tension-type headache criteria. The median duration of the headache was four (Inter-quartile range: two-six) days.

CONCLUSION

The clinical phenotype of headache attributed to influenza infection was similar to other infections, with more pronounced cranial autonomic symptoms. The headache was an early symptom and was self-limited within a few days.Trial Registration: The study protocol is registered in ClinicalTrial.gov (NCT05704335).

Outcomes of viral coinfections in infants hospitalized for acute bronchiolitis

BACKGROUND AND OBJECTIVE

The clinical relevance of the detection of multiple respiratory viruses in acute bronchiolitis (AB) has not been established. Our goal was to evaluate the effect of viral coinfections on the progression and severity of AB.

METHODS

A retrospective observational study was conducted in a tertiary hospital in Spain from September 2012 to March 2020. Infants admitted for AB with at least one respiratory virus identified by molecular diagnostic techniques were included. A comparison was made between single-virus infections and viral coinfections. The evolution and severity of AB were determined based on the days of hospitalization and admission to the pediatric intensive care unit (PICU).

RESULTS

Four hundred forty-five patients were included (58.4% male). The median weight was 5.2 kg (IQR 4.2-6.5), and the median age was 2.5 months (IQR 1.4-4.6). A total of 105 patients (23.6%) were admitted to the PICU. Respiratory syncytial virus (RSV) was the most frequent etiological agent (77.1%). A single virus was detected in 270 patients (60.7%), and viral coinfections were detected in 175 (39.3%), of which 126 (28.3%) had two viruses and 49 (11%) had three or more viruses. Hospital length of stay (LOS) increased in proportion to the number of viruses detected, with a median of 6 days (IQR 4-8) for single infections, 7 days (IQR 4-9) for coinfections with two viruses and 8 days (IQR 5-11) for coinfections with ≥ 3 viruses (p = 0.003). The adjusted Cox regression model showed that the detection of ≥ 3 viruses was an independent risk factor for a longer hospital LOS (HR 0.568, 95% CI 0.410-0.785). No significant association was observed between viral coinfections and the need for PICU admission (OR 1.151; 95% CI 0.737-1.797).

CONCLUSIONS

Viral coinfections modified the natural history of AB, prolonging the hospital LOS in proportion to the number of viruses detected without increasing the need for admission to the PICU.

Long-term influenza antibodies profiles in previously vaccinated and non-vaccinated adults

The aim of this work is to describe the dynamics of influenza antibodies after vaccination in adults. We conducted a case-cohort serological study in the automobile manufacturing plants of the Renault España S.A. group in Valladolid and Palencia (Spain), including 550 workers (66.9%) previously vaccinated against influenza (group V), and 272 (33.1%) never vaccinated (group NV). A pre-vaccination serum sample was collected, another after 30-40 days and another after 6 months. The dynamics of antibodies were analyzed. A lower seroprotection of NV before vaccination was observed, but an antibody response between 2 and 4 times higher than in V was assessed. After 6 months, antibodies declined in both groups until equalize. Antibodies titers decrease with age, and no differences were found among underlying pathologies. Adults never vaccinated against influenza had lower seroprotection than those previously vaccinated, but influenza vaccination produces a more intense serological response in them, acquiring significantly higher antibody titers than those previously vaccinated. The antibodies, although in lower titers, persist and equalize among both groups at least 6 months after vaccination, which allows the individual to be protected during the entire circulation of the influenza virus in the same season.

Possible Mpox Protection from Smallpox Vaccine-Generated Antibodies among Older Adults

Smallpox vaccination may confer cross-protection to mpox. We evaluated vaccinia virus antibodies in 162 persons ≥50 years of age in Spain; 68.5% had detectable antibodies. Highest coverage (78%) was among persons 71-80 years of age. Low antibody levels in 31.5% of this population indicates that addressing their vaccination should be a priority.

Evolution of antibody profiles against SARS-CoV-2 in experienced and naïve vaccinated elderly people

Introduction

The third dose of the COVID-19 vaccine is especially necessary in people over 65 years of age due to their lower immune response.

Methods

We designed a multicentre, prospective observational study including 98 people ≤65 years old who lived in two nursing homes in Valladolid, Spain. One of the groups had previous experience with SARS-CoV-2 (n=68;69.4%) and the other was naïve (n=30;30.6%). We evaluated the response to the three doses of the Comirnaty vaccine and the dynamics of antibodies during 5 consecutive serum samplings: 2 after the first two doses of vaccination, one three months after the first dose, another at 6 months and the last one month after the third dose. IgG antibodies against SARS-CoV-2 S1, RBD and N antigens were analysed.

Results

Both groups increased the level of Abs against S1 and RBD, but the experienced group showed a 130-fold higher humoral response due to hybrid immunisation (infection+vaccination). The response to vaccination with Comirnaty against COVID-19 was higher in those ≤65 years with previous experience than those who were naïve. However, the amount of antibodies against S1 and RBD equalised at 6 months. After the third dose, both groups raised the amount of antibodies to a similar level. The reinfections suggested by the analysis of antibodies against N were frequent in both groups.

Discussion

The third dose showed a clear benefit for elderly people, with the reinforcement of the antibody levels after the decline suffered after six months of the first two doses.

PCR-based diagnosis of respiratory virus in postsurgical septic patients: A preliminary study before SARS-CoV-2 pandemic

Respiratory viruses are part of the normal microbiota of the respiratory tract, which sometimes cause infection with/without respiratory insufficiency and the need for hospital or ICU admission. The aim of this study is to determine the prevalence of respiratory viruses in nontransplanted postoperative septic patients as well as lymphocyte count influence in their presence and its relationship to mortality. 223 nontransplanted postsurgical septic patients were recruited on the Intensive Care Unit (ICU) at Hospital Clínico Universitario de Valladolid prior to the SARS-COV-2 pandemic. Patients were split into 2 groups according to the presence/absence of respiratory viruses. Multivariate logistic regression analysis was used to identify independent factors related to positive respiratory virus PCR test. Respiratory viruses were isolated in 28.7% of patients. 28-day mortality was not significantly different between virus-positive and virus-negative groups. Logistic regression analysis revealed that lymphocyte count ≤ 928/µl is independently associated with a positive PCR result [OR 3.76, 95% CI (1.71-8.26), P = .001] adjusted by platelet count over 128,500/µL [OR 4.27, 95% CI (1.92-9.50) P < .001] and the presence of hypertension [OR 2.69, 95% CI (1.13-6.36) P = .025] as confounding variables. Respiratory viruses' detection by using PCR in respiratory samples of nontransplanted postoperative septic patients is frequent. These preliminary results revealed that the presence of lymphopenia on sepsis diagnosis is independently associated to a positive virus result, which is not related to a higher 28-day mortality.

Influenza B Lineages Have More in Common Than Meets the Eye. Trivalent Influenza Vaccines Trigger Heterotypic Antibodies Against Both Influenza B Viruses

Influenza B is accountable for an important burden during flu epidemics, causing special impact in children and the elderly. Vaccination is the best approach to address influenza infections. However, one of the main problems of this virus is that two different lineages circulate together, Victoria and Yamagata; and trivalent vaccines, that only contain one of these lineages, are still in use. For that reason, if during an epidemic, the lineage not included in the vaccine predominates, a mismatch would occur, and the vaccine effectiveness will be very poor. In this work, we evaluated the cross-protection given by the trivalent Influenza vaccine and compared serological profiles based on age, sex, and the type of vaccine used. We performed a retrospective analysis of serum samples obtained before and after seasonal influenza vaccination during 20 seasons (1998–2018). The results showed that heterotypic reactivity between both influenza B lineages is common, but always lower than the homologous response. Age is a relevant factor for this cross-reactivity between both lineages, while the sex and the type of vaccine not. Vaccination with trivalent influenza vaccines elicits cross-reactive antibodies against both lineages, however, this response might not be enough to provide an appropriate serological protection in case of mismatch.

[Encephalitis due to the Epstein-Barr virus: a description of a clinical case and review of the literature]

INTRODUCTION. Infection by the Epstein-Barr virus (EBV) -either as a primary infection, a reactivation or an active chronic infection- can give rise to several clinical forms of involvement of the central nervous system. We report a case of encephalitis due to EBV produced by viral reactivation in an immunocompetent patient which initially mimicked, from the clinical and electroencephalographic point of view, encephalitis due to type 1 herpes simplex virus (HSV-1). CASE REPORT. A 51-year-old male who had reported the presence of dorsal herpes zoster some days earlier. The patient visited the emergency department after suffering a holocranial oppressive headache and febricula for seven days; 24 hours before admission to hospital, he was suffering from drowsiness and language disorder. The neurological examination revealed stiffness in the back of the neck and dysphasia. An analysis of the cerebrospinal fluid revealed pleocytosis (422 cells/mm(3)) with 98% of mononuclear cells and normal protein and glucose concentration levels in cerebrospinal fluid. Magnetic resonance imaging of the brain and electroencephalogram readings were normal with periodic lateralised epileptiform discharges in the left temporal region. Intravenous acyclovir treatment was initiated, but renal failure meant it had to be changed to oral valaciclovir with clinical resolution and improvement of the liquoral parameters. Polymerase chain reaction in the cerebrospinal fluid was positive for EBV and negative for the other neurotropic viruses. In blood, the serology test for EBV with IgG was positive, while IgM and heterophile antibody tests were negative. CONCLUSIONS. EBV infection can give rise to acute disseminated encephalomyelitis or affect several locations in the central nervous system, especially the cerebellum. Clinical pictures mimicking HSV-1 are less frequent. When encephalitis is related to viral reactivation, precipitating factors can be detected, as in our case.