Epidemiology of the 2009 influenza pandemic in Spain. The Spanish Influenza Surveillance System.

In accordance with European Centre for Disease Prevention and Control recommendations, the Spanish Influenza Surveillance System (SISS) maintained its activity during the summer of 2009, and since July 2009 the pandemic virus activity was monitored by the SISS. In this paper, we describe the epidemiological and virological characteristics of the 2009 pandemic in the Spain through the SISS. Spain experienced a transmission of the new A(H1N1)pdm09 influenza virus during the summer of 2009, which gradually increased, resulting in the pandemic wave in early autumn of that year. The reproductive number R0, estimated during the growth phase of the pandemic wave (1.32; 95% confidence interval [95%CI], 1.29-1.36), showed a transmissibility comparable to preceding pandemics. There was an almost complete replacement of the previous seasonal A(H1N1) influenza virus by the pandemic virus A(H1N1)pdm09. The pandemic virus produced a greater burden of illness than seasonal influenza in children younger than 15 years old, while the incidence in those older than 64 years was lower compared with previous inter-pandemic seasons. Nevertheless, in Spain the 2009 pandemic was characterized as mild, considering the duration of the pandemic period and the influenza detection rate, both in the range of those observed in previous inter-pandemic seasons. Also, the case fatality ratio (CFR) was estimated at 0.58 deaths/1,000 confirmed ILI cases (95%CI, 0.52-0.64), in the range of the two previous pandemics of 1957 and 1968, with the highest CFR observed in the older than 64 years age group. In the 2009 pandemic there was a higher percentage of pandemic confirmed deaths in the younger ages, compared to seasonal influenza, since only 28% of the reported deaths occurred in persons aged 64 years and older.

Excretion and viability of SARS-CoV-2 in feces and its association with the clinical outcome of COVID-19.

The main objective was to evaluate the viability of the SARS-CoV-2 viral particles excreted in stools. In addition, we aimed to identify clinical factors associated with the detection of SARS-CoV-2 RNA in feces, and to determine if its presence is associated with an unfavorable clinical outcome, defined as intensive care unit (ICU) admission and/or death. A prospective multicenter cohort study of COVID-19 adult patients, with confirmed SARS-CoV-2 infection by RT-PCR assay in nasopharyngeal (NP) swabs admitted to four hospitals in Spain, from March 2020 to February 2021. Sixty-two adult COVID-19 patients had stool samples collected at admission and/or during the follow up, with a total of 79 stool samples. SARS-CoV-2 RNA was detected in stool samples from 27 (43.5%) out of the 62 patients. Replicative virus, measured by the generation of cytopathic effect in cell culture and subsequent RT-PCR confirmation of a decrease in the Ct values, was not found in any of these stool samples. Fecal virus excretion was not associated with the presence of gastrointestinal symptoms, or with differences in the evolution of COVID-19 patients. Our results suggest that SARS-CoV-2 replicative capacity is null or very limited in stool samples, and thus, the fecal-oral transmission of SARS-CoV-2 as an alternative infection route is highly unlikely. In our study, the detection of SARS-CoV-2 RNA in feces at the beginning of the disease is not associated with any clinical factor nor with an unfavorable clinical outcome.

A multicenter randomized open-label clinical trial for convalescent plasma in patients hospitalized with COVID-19 pneumonia.

BACKGROUNDPassive immunotherapy with convalescent plasma (CP) is a potential treatment for COVID-19. Evidence from controlled clinical trials is inconclusive.METHODSWe conducted a randomized, open-label, controlled clinical trial at 27 hospitals in Spain. Patients had to be admitted for COVID-19 pneumonia within 7 days from symptom onset and not on mechanical ventilation or high-flow oxygen devices. Patients were randomized 1:1 to treatment with CP in addition to standard of care (SOC) or to the control arm receiving only SOC. The primary endpoint was the proportion of patients in categories 5 (noninvasive ventilation or high-flow oxygen), 6 (invasive mechanical ventilation or extracorporeal membrane oxygenation [ECMO]), or 7 (death) at 14 days. Primary analysis was performed in the intention-to-treat population.RESULTSBetween April 4, 2020, and February 5, 2021, 350 patients were randomly assigned to either CP (n = 179) or SOC (n = 171). At 14 days, proportion of patients in categories 5, 6, or 7 was 11.7% in the CP group versus 16.4% in the control group (P = 0.205). The difference was greater at 28 days, with 8.4% of patients in categories 5-7 in the CP group versus 17.0% in the control group (P = 0.021). The difference in overall survival did not reach statistical significance (HR 0.46, 95% CI 0.19-1.14, log-rank P = 0.087).CONCLUSIONCP showed a significant benefit in preventing progression to noninvasive ventilation or high-flow oxygen, invasive mechanical ventilation or ECMO, or death at 28 days. The effect on the predefined primary endpoint at 14 days and the effect on overall survival were not statistically significant.TRIAL REGISTRATIONClinicaltrials.gov, NCT04345523.FUNDINGGovernment of Spain, Instituto de Salud Carlos III.

[Pandemic influenza A(H1N1): the experience of the Spanish Laboratories of Influenza Network (ReLEG)]. / Gripe pandémica H1N1 (2009): Experiencia de la Red de Laboratorios de Gripe del Sistema de Vigilancia de la Gripe en España (SVGE).

There are three types of influenza viruses: A, B, C. These viruses evolves constantly due to two main characteristics: the first one is the lack of the correction ability of the viral polymerase which causes the accumulation of single nucleotide mutations in the viral genes introduced by an error-prone viral RNA polymerase, (antigenic shift). The second one is the nature of their genome, formed by eight segments, which allows the interchange of genes between two different viral strains (antigenic drift). This viral plasticity, has allowed to the influenza A viruses to infect new host species and to cause infections with a pandemic characteristics. The Spanish influenza surveillance system, SVGE (its Spanish acronym), arises as a response to the possibility of facing a pandemic situation, especially after the transmission of avian influenza viruses to humans. This surveillance system is formed by sixteen physician and paediatrics network, nineteen epidemiological services coordinated by the National Epidemiological Centre (CNE) and eighteen laboratories , the Spanish Laboratories of Influenza network (ReLEG), coordinated by the National Centre of Microbiology. The aim of this article is to show the action of the ReLEG, in the pandemic caused by the influenza virus A(H1N1) during the season 2009-2010. The main objective of this network is the surveillance of the circulating viruses by means of their detection and their subsequent antigenic and genetic characterization, including the detection of resistance mutations against the main drugs, such as Oseltamivir.

[Asymptomatic infection by influenza AH1N1 virus in healthcare workers: MARBEGRIP study, preliminary results]. / Infección asintomática por el virus influenza H1N1 (2009) en personal sanitario: Estudio Marbegrip. Resultados preliminares.

BACKGROUND: The proportion of asymptomatic individuals infected by influenza AH1N1v varies depending on the studies. Health personnel were exposed to the AH1N1v virus due to their professional activity, thus an high seroprevalence to the virus could be expected in the absence of symptomatology. The objective of this study was to determine the prevalence of asymptomatic individuals serologically positive for influenza AH1N1v virus. METHODS: A cohort based prospective study on hospital staff was proposed according to an hypothetic decreasing gradient of exposure to the virus, from emergency personnel to medical and surgical areas, and auxiliary staff other than emergency personnel. Serum sample from each participant was taken in September-October, 2009, November-December, 2009, and in April-May, 2010; and a health questionnaire was simultaneously filled out. Specific antibodies against influenza AH1N1v were detected by hemagglutination inhibition test. Eighteen hospitals (1,371 individuals) participated in the study. RESULTS: Health questionnaire and serological results from four hospitals are available. A variable proportion of non vaccinated individuals showed positive serology (5.6-83%). Only 19.4% of subjects received vaccine, with a variable rate of positive serology (18.8-64.7%). Positive serology was significantly lower in non medical participants. In addition, vaccine coverage was higher in medical personnel than in the rest of professional categories. CONCLUSIONS: There was a variable percentage of influenza AH1N1v seropositive individuals who had not suffered clinical symptomatology. This serological study detects differences on vaccine efficacy.

[Biodefense: a new challenge for microbiology and public health]. / Biodefensa: un nuevo desafío para la microbiología y la salud pública.

Bioterrorism and the potential use of biological weapons has become an important concern of governments and responsible authorities. An example of this threat occurred in 2001 in the USA, when letters were sent containing spores of the agent that produces anthrax; this resulted in some deaths, and caused panic and negative effects on the world economy. If this small-scale event was able to cause such a huge impact, the repercussions of a massive attack could be catastrophic. In many countries, these events have resulted in the implementation of measures directed toward preventing and responding to bioterrorist threats and acts. As a whole, these measures are known as biodefense. This article briefly analyzes several aspects related to detecting and identifying acts of bioterrorism, and considers the biological agents that are implicated. The microbiological diagnosis that allows identification of the causal agent, a key point for taking suitable control measures, is also included.