12 research outputs found
Omicron infection enhances Delta antibody immunity in vaccinated persons
The extent to which Omicron infection(1–9), with or without previous vaccination, elicits protection against the previously dominant Delta (B.1.617.2) variant is unclear. Here we measured the neutralization capacity against variants of severe acute respiratory syndrome coronavirus 2 in 39 individuals in South Africa infected with the Omicron sublineage BA.1 starting at a median of 6 (interquartile range 3–9) days post symptom onset and continuing until last follow-up sample available, a median of 23 (interquartile range 19–27) days post symptoms to allow BA.1-elicited neutralizing immunity time to develop. Fifteen participants were vaccinated with Pfizer's BNT162b2 or Johnson & Johnson's Ad26.CoV2.S and had BA.1 breakthrough infections, and 24 were unvaccinated. BA.1 neutralization increased from a geometric mean 50% focus reduction neutralization test titre of 42 at enrolment to 575 at the last follow-up time point (13.6-fold) in vaccinated participants and from 46 to 272 (6.0-fold) in unvaccinated participants. Delta virus neutralization also increased, from 192 to 1,091 (5.7-fold) in vaccinated participants and from 28 to 91 (3.0-fold) in unvaccinated participants. At the last time point, unvaccinated individuals infected with BA.1 had low absolute levels of neutralization for the non-BA.1 viruses and 2.2-fold lower BA.1 neutralization, 12.0-fold lower Delta neutralization, 9.6-fold lower Beta variant neutralization, 17.9-fold lower ancestral virus neutralization and 4.8-fold lower Omicron sublineage BA.2 neutralization relative to vaccinated individuals infected with BA.1. These results indicate that hybrid immunity formed by vaccination and Omicron BA.1 infection should be protective against Delta and other variants. By contrast, infection with Omicron BA.1 alone offers limited cross-protection despite moderate enhancement
Association of predicted 10 years cardiovascular mortality risk with duration of HIV infection and antiretroviral therapy among HIV-infected individuals in Durban, South Africa
Background: South Africa has the largest population of human immunodeficiency virus (HIV) infected patients on antiretroviral therapy (ART) realising the benefits of increased life expectancy. However, this population may be susceptible to cardiovascular disease (CVD) development, due to the chronic consequences of a lifestyle-related combination of risk factors, HIV infection and ART. We predicted a 10-year cardiovascular mortality risk in an HIV-infected population on long-term ART, based on their observed metabolic risk factor profile. Methods: We extracted data from hospital medical charts for 384 randomly selected HIV-infected patients aged ≥ 30 years. We defined metabolic syndrome (MetS) subcomponents using the International Diabetes Federation definition. A validated non-laboratory-based model for predicting a 10-year CVD mortality risk was applied and categorised into five levels, with the thresholds ranging from very low-risk ( 30%). Results: Among the 384 patients, with a mean (± standard deviation) age of 42.90 ± 8.20 years, the proportion of patients that were overweight/obese was 53.3%, where 50.9% had low high-density lipoprotein (HDL) cholesterol and 21 (17.5%) had metabolic syndrome. A total of 144 patients with complete data allowed a definitive prediction of a 10-year CVD mortality risk. 52% (95% CI 44-60) of the patients were stratified to very low risk ( 30%) of 10-year CVD mortality. The CVD risk grows with increasing age (years), 57.82 ± 6.27 among very high risk and 37.52 ± 4.50; p < 0.001 in very low risk patients. Adjusting for age and analysing CVD risk mortality as a continuous risk score, increasing duration of HIV infection (p = 0.002) and ART (p = 0.007) were significantly associated with increased predicted 10 year CVD mortality risk. However, there was no association between these factors and categorised CVD mortality risk as per recommended scoring thresholds. Conclusions: Approximately 1 in 10 HIV-infected patients is at very high risk of predicted 10-year CVD mortality in our study population. Like uninfected individuals, our study found increased age as a major predictor of 10-year mortality risk and high prevalence of metabolic syndrome. Additional CVD mortality risk due to the duration of HIV infection and ART was seen in our population, further studies in larger and more representative study samples are encouraged. It recommends an urgent need for early planning, prevention and management of metabolic risk factors in HIV populations, at the point of ART initiation
Exposure to Human Immunodeficiency Disease. What Precautions for the Healthcare Professional?
Background: The Human Immunodeficiency Virus (HIV) epidemic is more
pronounced in sub- Saharan Africa. The ever-increasing prevalence of
HIV infection and the continued improvement in clinical management has
increased the likelihood of these patients being managed by healthcare
workers. The aim of the review was to assess current literature on the
risks of transmission of HIV infection and protection of the healthcare
worker. Methods: A literature review was performed using MEDLINE
articles addressing ‘human immunodeficiency virus’,
‘HIV’, ‘Acquired immunodeficiency syndrome’,
‘AIDS’, ‘HIV and Surgery’. We also manually
searched relevant surgical journals and completed the bibliographic
compilation by collecting cross references from published papers.
Results: Transmission is by contamination with body fluids for example
needle-stick injury and blood splashes. The risk of HIV transmission
from patient to healthcare worker always exists. The risk of
transmission is very small and depends on the type of discipline and
type of procedure. Hollow needles are more dangerous than suture
needles. Sero-conversion is, however, very minimal. Universal
precautions are emphasised. In case of needle-stick injury or splash it
is important that affected healthcare workers take post-exposure
prophylaxis. Conclusion: Occupational HIV transmission is lower than
that for other infections. However, protection of all health care
personnel should be the prime objective. Universal infection control
guidelines must be accepted and strictly enforced. A prompt response to
blood contact is crucial and post-exposure prophylaxis is essential
Incidence of chemotherapy-induced neutropenia in HIV-infected and uninfected patients with breast cancer receiving neoadjuvant chemotherapy
Background. Chemotherapy-induced neutropenia (CIN) can result in poor tolerance of chemotherapy, leading to dose reductions, delays in therapy schedules, morbidity and mortality. Actively identifying predisposing risk factors before treatment is of paramount importance. We hypothesised that chemotherapy is associated with a greater increase in CIN and its complications in HIV-infected patients than in those who are not infected.
Objective. To establish the incidence of CIN in HIV-infected and uninfected patients undergoing chemotherapy.
Methods. A retrospective chart review and analysis was conducted in the oncology departments at Inkosi Albert Luthuli Central Hospital and Addington Hospital, Durban, South Africa. The study population consisted of 65 previously untreated women of all ages with stage II - IV breast cancer and known HIV status treated with neoadjuvant chemotherapy from January 2012 to December 2015.
Results. HIV-infected patients formed 32.3% of the group, and 95.2% of them were on antiretroviral therapy. The mean age (standard deviation (SD)) of the cohort was 48.5 (13.2) years (40.6 (9.6) years for the HIV-infected group v. 52.0 (13.1) years for the uninfected group; p<0.001). Ninety-five neutropenia episodes were observed (rate 0.85 per 1 year of follow-up time). Following multivariate adjustment, patients with HIV infection were almost two times more likely to develop CIN (hazard ratio (HR) 1.76, 95% confidence interval (CI) 1.06 - 2.92; p=0.029. A high baseline absolute neutrophil count (ANC) (HR 0.80, 95% CI 0.68 - 0.95; p=0.005) remained significantly associated with protection against CIN.
Conclusions. HIV-infected patients were younger than those who were not infected, and presented at a more locally advanced stage of disease. HIV infection was an independent predictor for CIN. HIV-infected patients had an almost two-fold increased risk of developing CIN and developed neutropenia at a much faster rate. A high baseline white cell count and ANC were protective against CIN
Elastic stability of thin-walled cylindrical and conical shells under combined external pressure and axial compression
Omicron infection enhances Delta antibody immunity in vaccinated persons
The extent to which Omicron infection(1–9), with or without previous vaccination, elicits protection against the previously dominant Delta (B.1.617.2) variant is unclear. Here we measured the neutralization capacity against variants of severe acute respiratory syndrome coronavirus 2 in 39 individuals in South Africa infected with the Omicron sublineage BA.1 starting at a median of 6 (interquartile range 3–9) days post symptom onset and continuing until last follow-up sample available, a median of 23 (interquartile range 19–27) days post symptoms to allow BA.1-elicited neutralizing immunity time to develop. Fifteen participants were vaccinated with Pfizer's BNT162b2 or Johnson & Johnson's Ad26.CoV2.S and had BA.1 breakthrough infections, and 24 were unvaccinated. BA.1 neutralization increased from a geometric mean 50% focus reduction neutralization test titre of 42 at enrolment to 575 at the last follow-up time point (13.6-fold) in vaccinated participants and from 46 to 272 (6.0-fold) in unvaccinated participants. Delta virus neutralization also increased, from 192 to 1,091 (5.7-fold) in vaccinated participants and from 28 to 91 (3.0-fold) in unvaccinated participants. At the last time point, unvaccinated individuals infected with BA.1 had low absolute levels of neutralization for the non-BA.1 viruses and 2.2-fold lower BA.1 neutralization, 12.0-fold lower Delta neutralization, 9.6-fold lower Beta variant neutralization, 17.9-fold lower ancestral virus neutralization and 4.8-fold lower Omicron sublineage BA.2 neutralization relative to vaccinated individuals infected with BA.1. These results indicate that hybrid immunity formed by vaccination and Omicron BA.1 infection should be protective against Delta and other variants. By contrast, infection with Omicron BA.1 alone offers limited cross-protection despite moderate enhancement