scholarly journals Patterns of SARS-CoV-2 exposure and mortality suggest endemic infections, in addition to space and population factors, shape dynamics across countries

Author(s):  
Nicholas M Fountain-Jones ◽  
Luke Yates ◽  
Emily Flies ◽  
Andrew Flies ◽  
Scott Carver ◽  
...  

Some countries have been crippled by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic while others have emerged with few infections and fatalities; the factors underscoring this macro-epidemiological variation is one of the mysteries of this global catastrophe. Variation in immune responses influence SARS-CoV-2 transmission and mortality, and factors shaping this variation at the country level, in addition to other socio-ecological drivers, may be important. Here, we construct spatially explicit Bayesian models that combine data on prevalence of endemic diseases and other socio-ecological characteristics to quantify patterns of confirmed deaths and cases across the globe before mass vaccination. We find that the prevalence of parasitic worms, human immunodeficiency virus and malaria play a surprisingly important role in predicting country-level SARS-CoV-2 patterns. When combined with factors such as population density, our models predict 63% (56-67) and 76% (69-81) of confirmed cases and deaths among countries, respectively. While our findings at this macro-scale are necessarily associative, they highlight a need for studies to consider factors, such as infection by other pathogens, on global SARS-CoV-2 dynamics. These relationships are vital for developing countries that already have the highest burden of endemic disease and are becoming the most affected by the SARS-CoV-2 pandemic.

2008 ◽  
Vol 83 (2) ◽  
pp. 584-597 ◽  
Author(s):  
Elena Carnero ◽  
Wenjing Li ◽  
Antonio V. Borderia ◽  
Bruno Moltedo ◽  
Thomas Moran ◽  
...  

ABSTRACT One attractive strategy for the development of a human immunodeficiency virus (HIV) vaccine is the use of viral vectors with a proven safety profile and an absence of preexisting immunity in humans, such as Newcastle disease virus (NDV). Several NDV vaccine vectors have been generated, and their immunogenicities have been investigated with different animal models. However, a systematic study to evaluate the optimal insertion site of the foreign antigens into NDV that results in enhanced immune responses specific to the antigen has not yet been conducted. In this article, we describe the ability of NDV expressing HIV Gag to generate a Gag-specific immune response in mice. We also have determined the optimal insertion site into the NDV genome by generating recombinant NDV-HIVGag viruses in which HIV gag was located at different transcriptional positions throughout the NDV viral genome. All recombinant viruses were viable, grew to similar titers in embryonated chicken eggs, and expressed Gag in a stable manner. Our in vivo experiments revealed that higher HIV Gag protein expression positively correlates with an enhanced CD8+ T-cell-mediated immune response and protective immunity against challenge with vaccinia virus expressing HIV Gag. We also inserted a codon-optimized version of HIV gag in the described best location, between the P and M genes. Virus expressing the codon-optimized version of HIV gag induced a higher expression of the protein and an enhanced immune response against HIV Gag in mice. These results indicate that strategies directed toward increasing antigen expression by NDV result in enhanced immunogenicity and vaccine efficacy.


2005 ◽  
Vol 86 (2) ◽  
pp. 339-348 ◽  
Author(s):  
L. Lopalco ◽  
C. Barassi ◽  
C. Paolucci ◽  
D. Breda ◽  
D. Brunelli ◽  
...  

Unconventional immune responses have been demonstrated in individuals who, despite repeated exposure to human immunodeficiency virus (HIV) infection, remain seronegative. As environmental exposure to pathogens and genetic background may modulate immune responses differentially, one Italian and two Asian populations of HIV-1-exposed seronegative individuals were studied. In serum samples from each group, IgG to CCR5, IgG to CD4 and IgA to gp41 were measured, which were previously described as markers of unconventional immunity in HIV-exposed seronegative Caucasians. Given the importance of conformational epitopes in virus–cell interactions, IgG to CD4–gp120 complex was also measured. It was found that markers of HIV exposure were present in all populations studied. HIV-specific humoral responses (IgA to gp41 and IgG to CD4–gp120 complex) were extremely significant predictors of HIV exposure (P<0·0001 in both cases), whereas the predictive values of anti-cell antibodies (anti-CCR5 and anti-CD4) varied between populations. Evidence is provided for the correlation of these differences with route of exposure to HIV and level of natural antibodies to cross-reactive microbial antigens. In conclusion, exposed seronegative individuals of ethnically different origins display similar signs of HIV-dependent unconventional immunity. A specific relevance must be attributed to different innate and acquired factors.


2005 ◽  
Vol 12 (1) ◽  
pp. 165-170 ◽  
Author(s):  
David Tarragó ◽  
Julio Casal ◽  
Jesús Ruiz-Contreras ◽  
J. Tomás Ramos ◽  
Pablo Rojo ◽  
...  

ABSTRACT We investigated antibody responses against pneumococci of serotypes 6B, 14, and 23F in 56 children and adolescents with perinatal human immunodeficiency virus (HIV) infection who were vaccinated with 7-valent pneumococcal conjugate vaccine. Overall immune responses differed greatly between serotypes. Correlation coefficients between immunoglobulin G (IgG) measured by enzyme-linked immunosorbent assay (ELISA) and functional antibodies measured by a flow cytometry opsonophagocytosis assay (OPA) varied with serotype and time points studied. After 3 months of administering a second PCV7 dose we got the highest correlation (with significant r values of 0.754, 0.414, and 0.593 for serotypes 6B, 14, and 23F, respectively) but no significant increase in IgG concentration and OPA titers compared to the first dose. We defined a responder to a serotype included in the vaccine with two criteria: frequency of at least twofold OPA and ELISA increases for each serotype and frequency of conversion from negative to positive OPA levels. Responders varied from 43.9% to 46.3%, 28.5% to 50.0%, and 38.0% to 50.0% for serotypes 6B, 14, and 23F, respectively, depending on the response criterion. The present research highlights the importance of demonstrating vaccine immunogenicity with suitable immunological endpoints in immunocompromised patients and also the need to define how much antibody is required for protection from different serotypes, since immunogenicity differed significantly between serotypes.


2001 ◽  
Vol 75 (3) ◽  
pp. 1547-1550 ◽  
Author(s):  
S. Cherpelis ◽  
I. Shrivastava ◽  
A. Gettie ◽  
X. Jin ◽  
D. D. Ho ◽  
...  

ABSTRACT DNA immunization of macaques with the SF162ΔV2 envelope elicited lymphoproliferative responses and potent neutralizing antibodies. The animals were depleted of their CD8+ T lymphocytes and then challenged intravenously with SHIV162P4. Compared to unvaccinated animals, the vaccinated macaques had lower peak viremia levels, rapidly cleared plasma virus, and showed delayed seroconversion.


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