past infection
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Author(s):  
Yeray Nóvoa-Medina ◽  
Svetlana Pavlovic-Nesic ◽  
Jesús Ma González-Martín ◽  
Araceli Hernández-Betancor ◽  
Sara López ◽  
...  

Abstract Objectives It has been hypothesized that SARS-CoV-2 may play a role in the development of different forms of diabetes mellitus (DM). The Canary Islands have the highest incidence of type 1 DM (T1DM) reported in Spain (30–35/100,000 children under 14 years/year). In 2020–2021 we observed the highest incidence so far on the island of Gran Canaria, as a result of which we decided to evaluate the possible role of COVID-19 in the increased number of onsets. Methods We examined the presence of IgG antibodies against SARS-CoV-2 in children with new onset T1DM between October 2020 and August 2021. We compared recent T1DM incidence with that of the previous 10 years. Results Forty-two patients were diagnosed with T1DM (48.1/100,000 patients/year), representing a nonsignificant 25.7% increase from the expected incidence. Of the 33 patients who consented to the study, 32 presented negative IgG values, with only one patient reflecting undiagnosed past infection. Forty-four percent of patients presented with ketoacidosis at onset, which was similar to previous years. Conclusions We conclude that there is no direct relationship between the increased incidence of T1DM and SARS-CoV-2 in the region. The COVID-19 pandemic did not result in an increased severity of T1DM presentation.


2022 ◽  
Author(s):  
Malik Peiris ◽  
Samuel Cheng ◽  
Chris Ka Pun Mok ◽  
Yonna Leung ◽  
Susanna Ng ◽  
...  

Abstract Omicron, a novel SARS-CoV-2 variant has emerged and is rapidly becoming the dominant SARS-CoV-2 virus circulating globally. It is important to define reductions in virus neutralizing activity in serum of convalescent or vaccinated individuals to understand potential loss of protection from infection or re-infection. Two doses of BNT162b2 or CoronaVac vaccines provided little 50% plaque reduction neutralization test (PRNT50) antibody immunity against the Omicron variant, even at one-month post vaccination. Booster doses with BNT162b2 in those with two doses of either BNT162b2 or CoronaVac provided acceptable neutralizing immunity against Omicron variant at 1-month post-booster dose. However, three doses of BNT162b2 elicited higher levels of PRNT50 antibody to Omicron variant suggesting longer duration of protection. Convalescent from SARS-CoV-2 infection did not have protective PRNT50 antibody levels to Omicron, but a single dose of BNT162b2 vaccine provided protective immunity. Field vaccine-efficacy studies against Omicron variant against different vaccines are urgently needed.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260453
Author(s):  
Ville N. Pimenoff ◽  
Miriam Elfström ◽  
Kalle Conneryd Lundgren ◽  
Susanna Klevebro ◽  
Erik Melen ◽  
...  

A majority of SARS-CoV-2 infections are transmitted from a minority of infected subjects, some of which may be symptomatic or pre-symptomatic. We aimed to quantify potential infectiousness among asymptomatic healthcare workers (HCWs) in relation to prior or later symptomatic disease. We previously (at the onset of the SARS-CoV-2 epidemic) performed a cohort study of SARS-CoV-2 infections among 27,000 healthcare workers (HCWs) at work in the capital region of Sweden. We performed both SARS-CoV-2 RT-PCR and serology. Furthermore, the cohort was comprehensively followed for sick leave, both before and after sampling. In the present report, we used the cohort database to quantify potential infectiousness among HCWs at work. Those who had sick leave either before or after sampling were classified as post-symptomatic or pre-symptomatic, whereas the virus-positive subjects with no sick leave were considered asymptomatic. About 0.2% (19/9449) of HCW at work were potentially infectious and pre-symptomatic (later had disease) and 0.17% (16/9449) were potentially infectious and asymptomatic (never had sick leave either before nor after sampling). Thus, 33% and 28% of all the 57 potentially infectious subjects were pre-symptomatic or asymptomatic, respectively. When a questionnaire was administered to HCWs with past infection, only 10,5% of HCWs had had no indication at all of having had SARS-CoV-2 infection (“truly asymptomatic”). Our findings provide a unique quantification of the different groups of asymptomatic, potentially infectious HCWs.


Author(s):  
Jun Bai ◽  
Zuo-zhen Yang ◽  
Hao Li ◽  
Yun Hong ◽  
Dong-dong Fan ◽  
...  

Endogenous retroviruses (ERVs) are relics of past infection that constitute up to 8% of the human genome. Understanding the genetic evolution of the ERV family and the interplay of ERVs and encoded RNAs and proteins with host function has become a new frontier in biology.


2021 ◽  
Vol 10 (24) ◽  
pp. 5882
Author(s):  
Ioannis Mamais ◽  
Apostolos Malatras ◽  
Gregory Papagregoriou ◽  
Natasa Giallourou ◽  
Andrea C. Kakouri ◽  
...  

Long-term persistence and the heterogeneity of humoral response to SARS-CoV-2 have not yet been thoroughly investigated. The aim of this work is to study the production of circulating immunoglobulin class G (IgG) antibodies against SARS-CoV-2 in individuals with past infection in Cyprus. Individuals of the general population, with or without previous SARS-CoV-2 infection, were invited to visit the Biobank at the Center of Excellence in Biobanking and Biomedical Research of the University of Cyprus. Serum IgG antibodies were measured using the SARS-CoV-2 IgG and the SARS-CoV-2 IgG II Quant assays of Abbott Laboratories. Antibody responses to SARS-CoV-2 were also evaluated against participants’ demographic and clinical data. All statistical analyses were conducted in Stata 16. The median levels of receptor binding domain (RBD)-specific IgG in 969 unvaccinated individuals, who were reportedly infected between November 2020 and September 2021, were 432.1 arbitrary units (AI)/mL (interquartile range—IQR: 182.4–1147.3). Higher antibody levels were observed in older participants, males, and those who reportedly developed symptoms or were hospitalized. The RBD-specific IgG levels peaked at three months post symptom onset and subsequently decreased up to month six, with a slower decay thereafter. IgG response to the RBD of SARS-CoV-2 is bi-phasic with considerable titer variability. Levels of IgG are significantly associated with several parameters, including age, gender, and severity of symptoms.


Author(s):  
Ihza Rizkia Fitri ◽  
◽  
Toni Bakhtiar ◽  

The SARS-CoV-2 outbreak that started in China created COVID-19 pandemic all around the world. This pandemic is declared as a world health crisis by the World Health Organization in 2020. In response to this pandemic, many countries have been conducting various measures to manage the spread of the disease employing lockdown, contacts tracing, and massive testing. As the vaccine and medicine for this virus are under development, the governments all around the world can only apply non-curative measures. With many considerations, especially in the economic sector, governments seem hesitant to apply extensive control measures and this results in a considerable financial loss. In this paper, a generic mathematical model with thirteen compartments is developed, of which it is equipped with five control measures namely quarantine, active carrier identification, recovered individual identification, past infection identification, and medical treatment. We employ the COVID-19 outbreak in Jakarta as a study case to evaluate a series of control scenarios. Optimal control approach is used to find the best control strategy in managing the pandemic. It is suggested that adding the efforts on testing policy and medical treatment 40 days after the first confirmed infection is the most cost-effective strategy with the number of death decreased as much as 60:21 percent of the death cases under initial control strategy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sho Tsuyuki ◽  
Hideyuki Takeshima ◽  
Shigeki Sekine ◽  
Yukinori Yamagata ◽  
Takayuki Ando ◽  
...  

AbstractGastric cancers can develop even after Helicobacter pylori (H. pylori) eradication in 0.2–2.9% cases per year. Since H. pylori is reported to directly activate or inactivate cancer-related pathways, molecular profiles of gastric cancers with current and past H. pylori infection may be different. Here, we aimed to analyze whether profiles of point mutation and gene amplification are different between the two groups. Current or past infection by H. pylori was determined by positive or negative amplification of H. pylori jhpr3 gene by PCR, and past infection was established by the presence of endoscopic atrophy. Among the 90 gastric cancers analyzed, 55 were with current infection, and 35 were with past infection. Target sequencing of 46 cancer-related genes revealed that 47 gastric cancers had 68 point mutations of 15 different genes, such as TP53 (36%), KRAS (4%), and PIK3CA (4%) and that gene amplification was present for ERBB2, KRAS, PIK3CA, and MET among the 26 genes assessed for copy number alterations. Gastric cancers with current and past infection had similar frequencies of TP53 mutations (38% and 31%, respectively; p = 0.652) and oncogene activation (20% and 29%, respectively; p = 0.444). Gastric cancers with current and past infection had comparable profiles of genetic alterations.


2021 ◽  
pp. 3851-3857
Author(s):  
Zainab M. Lateef ◽  
Alice K. Melconian ◽  
Ehab D. Salman

Chlamydia pneumoniae is an intracellular gram-negative bacteria associated with lower and upper respiratory tract infections. Several studies, mostly achieved by serological assays, proposed a role for this bacteria in lung cancer risk. Therefore, this study aimed to evaluate the prevalence of Chlamydia pneuomoniae in fresh lung tissues of a sample of Iraqi patients with lung tumors, utilizing polymerase chain reaction (PCR) technique. . Chlamydia pneumoniae DNA was detected in 86.67% of samples. Besides, DNA sequencing of 16S rRNA gene revealed that our isolate is closely related to Chlamydia pneumoniae TW183 strain. It is concluded that Chlamydia pneumoniae  is found in fresh lung tissues of patients, suggesting past infection, reinfection, or persistent form, which may play a role in the development or exacerbation of lung tumors. Our results confirm the high prevalence of this type of bacteria in Iraqi patients.


2021 ◽  
Vol 79 (1) ◽  
Author(s):  
Maria E. Goossens ◽  
Kristof Y. Neven ◽  
Pieter Pannus ◽  
Cyril Barbezange ◽  
Isabelle Thomas ◽  
...  

Abstract Background The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has presented itself as one of the most important health concerns of the 2020’s, and hit the geriatric population the hardest. The presence of co-morbidities and immune ageing in the elderly lead to an increased susceptibility to COVID-19, as is the case for other influenza-like illnesses (ILI) or acute respiratory tract infections (ARI). However, little is known, about the impact of a previous or current infection on the other in terms of susceptibility, immune response, and clinical course. The aim of the “Prior Infection with SARS-COV-2” (PICOV) study is to compare the time to occurrence of an ILI or ARI between participants with a confirmed past SARS-CoV-2 infection (previously infected) and those without a confirmed past infection (naïve) in residents and staff members of nursing homes. This paper describes the study design and population characteristics at baseline. Methods In 26 Belgian nursing homes, all eligible residents and staff members were invited to participate, resulting in 1,226 participants. They were classified as naïve or previously infected based on the presence of detectable SARS-CoV-2 antibodies and/or a positive RT-qPCR result before participation in the study. Symptoms from a prior SARS-CoV-2 infection between March and August 2020 were compared between previously infected residents and staff members. Results Infection naïve nursing home residents reported fewer symptoms than previously infected residents: on average 1.9 and 3.1 symptoms, respectively (p = 0.016). The same effect was observed for infection naïve staff members and previously infected staff members (3.1 and 6.1 symptoms, respectively; p <0.0001). Moreover, the antibody development after a SARS-CoV-2 infection differs between residents and staff members, as previously infected residents tend to have a higher rate of asymptomatic cases compared to previously infected staff members (20.5% compared to 12.4%; p <0.0001). Conclusions We can postulate that COVID-19 disease development and symptomatology are different between a geriatric and younger population. Therefore, the occurrence and severity of a future ILI and/or ARI might vary from resident to staff.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259703
Author(s):  
Ashley N. Gray ◽  
Rachel Martin-Blais ◽  
Nicole H. Tobin ◽  
Yan Wang ◽  
Sarah L. Brooker ◽  
...  

Two mRNA vaccines (BNT162b2 and mRNA-1273) against severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) are globally authorized as a two-dose regimen. Understanding the magnitude and duration of protective immune responses is vital to curbing the pandemic. We enrolled 461 high-risk health services workers at the University of California, Los Angeles (UCLA) and first responders in the Los Angeles County Fire Department (LACoFD) to assess the humoral responses in previously infected (PI) and infection naïve (NPI) individuals to mRNA-based vaccines (BNT162b2/Pfizer- BioNTech or mRNA-1273/Moderna). A chemiluminescent microparticle immunoassay was used to detect antibodies against SARS-CoV-2 Spike in vaccinees prior to (n = 21) and following each vaccine dose (n = 246 following dose 1 and n = 315 following dose 2), and at days 31–60 (n = 110) and 61–90 (n = 190) following completion of the 2-dose series. Both vaccines induced robust antibody responses in all immunocompetent individuals. Previously infected individuals achieved higher median peak titers (p = 0.002) and had a slower rate of decay (p = 0.047) than infection-naïve individuals. mRNA-1273 vaccinated infection-naïve individuals demonstrated modestly higher titers following each dose (p = 0.005 and p = 0.029, respectively) and slower rates of antibody decay (p = 0.003) than those who received BNT162b2. A subset of previously infected individuals (25%) required both doses in order to reach peak antibody titers. The biologic significance of the differences between previously infected individuals and between the mRNA-1273 and BNT162b2 vaccines remains uncertain, but may have important implications for booster strategies.


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