A Trial of a 7-Valent Pneumococcal Conjugate Vaccine in HIV-Infected Adults.

BACKGROUND: Streptococcus pneumoniae is a leading and serious coinfection in adults with human immunodeficiency virus (HIV) infection, particularly in Africa. Prevention of this disease by vaccination with the current 23-valent polysaccharide vaccine is suboptimal. Protein conjugate vaccines offer a further option for protection, but data on their clinical efficacy in adults are needed. METHODS: In this double-blind, randomized, placebo-controlled clinical efficacy trial, we studied the efficacy of a 7-valent conjugate pneumococcal vaccine in predominantly HIV-infected Malawian adolescents and adults who had recovered from documented invasive pneumococcal disease. Two doses of vaccine were given 4 weeks apart. The primary end point was a further episode of pneumococcal infection caused by vaccine serotypes or serotype 6A. RESULTS: From February 2003 through October 2007, we followed 496 patients (of whom 44% were male and 88% were HIV-seropositive) for 798 person-years of observation. There were 67 episodes of pneumococcal disease in 52 patients, all in the HIV-infected subgroup. In 24 patients, there were 19 episodes that were caused by vaccine serotypes and 5 episodes that were caused by the 6A serotype. Of these episodes, 5 occurred in the vaccine group and 19 in the placebo group, for a vaccine efficacy of 74% (95% confidence interval [CI], 30 to 90). There were 73 deaths from any cause in the vaccine group and 63 in the placebo group (hazard ratio in the vaccine group, 1.18; 95% CI, 0.84 to 1.66). The number of serious adverse events within 14 days after vaccination was significantly lower in the vaccine group than in the placebo group (3 vs. 17, P=0.002), and the number of minor adverse events was significantly higher in the vaccine group (41 vs. 13, P=0.003). CONCLUSIONS: The 7-valent pneumococcal conjugate vaccine protected HIV-infected adults from recurrent pneumococcal infection caused by vaccine serotypes or serotype 6A. (Current Controlled Trials number, ISRCTN54494731.) Copyright 2010 Massachusetts Medical Society

Nanocarriers Targeting Dendritic Cells for Pulmonary Vaccine Delivery

Pulmonary vaccine delivery has gained significant attention as an alternate route for vaccination without the use of needles. Immunization through the pulmonary route induces both mucosal and systemic immunity, and the delivery of antigens in a dry powder state can overcome some challenges such as cold-chain and availability of medical personnel compared to traditional liquid-based vaccines. Antigens formulated as nanoparticles (NPs) reach the respiratory airways of the lungs providing greater chance of uptake by relevant immune cells. In addition, effective targeting of antigens to the most ‘professional’ antigen presenting cells (APCs), the dendritic cells (DCs) yields an enhanced immune response and the use of an adjuvant further augments the generated immune response thus requiring less antigen/dosage to achieve vaccination. This review discusses the pulmonary delivery of vaccines, methods of preparing NPs for antigen delivery and targeting, the importance of targeting DCs and different techniques involved in formulating dry powders suitable for inhalation

Nanocarriers Targeting Dendritic Cells for Pulmonary Vaccine Delivery

Pulmonary vaccine delivery has gained significant attention as an alternate route for vaccination without the use of needles. Immunization through the pulmonary route induces both mucosal and systemic immunity, and the delivery of antigens in a dry powder state can overcome some challenges such as cold-chain and availability of medical personnel compared to traditional liquid-based vaccines. Antigens formulated as nanoparticles (NPs) reach the respiratory airways of the lungs providing greater chance of uptake by relevant immune cells. In addition, effective targeting of antigens to the most ‘professional’ antigen presenting cells (APCs), the dendritic cells (DCs) yields an enhanced immune response and the use of an adjuvant further augments the generated immune response thus requiring less antigen/dosage to achieve vaccination. This review discusses the pulmonary delivery of vaccines, methods of preparing NPs for antigen delivery and targeting, the importance of targeting DCs and different techniques involved in formulating dry powders suitable for inhalation

Blood culture collection technique and pneumococcal surveillance in Malawi during the four year period 2003–2006: an observational study

BACKGROUND: Blood culture surveillance will be used for assessing the public health effectiveness of pneumococcal conjugate vaccines in Africa. Between 2003 and 2006 we assessed blood culture outcome and performance in adult patients in the central public hospital in Blantyre, Malawi, before and after the introduction of a dedicated nurse led blood culture team. METHODS: A prospective observational study. RESULTS: Following the introduction of a specialised blood culture team in 2005, the proportion of contaminated cultures decreased (19.6% in 2003 to 5.0% in 2006), blood volume cultured increased and pneumococcal recovery increased significantly from 2.8% of all blood cultures to 6.1%. With each extra 1 ml of blood cultured the odds of recovering a pneumococcus increased by 18%. CONCLUSION: Standardisation and assessment of blood culture performance (blood volume and contamination rate) should be incorporated into pneumococcal disease surveillance activities where routine blood culture practice is constrained by limited resources

Simultaneous Quantification of Lamivudine, Zidovudine and Related Impurities in Fixed Oral Dosage Combination Using RP-HPLC with DAD detection

A simple and fast isocratic Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method has been developed and validated for the simultaneous determination of Lamivudine, zidovudine and their related impurities in tablets. The method consists of a mobile phase combination of Acetonitrile (HPLC grade) and Buffer (0.0680 g of Potassium Dihydrogen Orthophosphate, 0.3 ml of Triethylamine, pH adjusted to 8.0 with Orthophosphoric acid to a final volume preparation of 100 ml) in the ratio 10:90. Phenomenex Luna 5-µm C18 (2)-250 x 4.6-mm, 5-µm) was used as the stationary phase. The column oven was set to a temperature of 30±1oC. Quantification was achieved with a DAD detector set at 270 nm. Resolution was achieved at a short run time of 25 minutes. Zidovudine related impurity C, Lamivudine, salicylic acid, Zidovudine and Zidovudine related impurity B eluted at 3.749±0.004, 4.862±0.013, 15.332±0.064, 21.201±0.076 and 23.682±0.117 respectively. Relative retention times (RRT) for lamivudine unknown related impurities with respect to Zidovudine were 0.15, 0.17, 0.30 and 0.59. RRT for Zidovudine unknown related impurities with respect to Zidovudine were 0.39 and 0.63.  The method was found to be specific, robust, accurate and precise for the estimation of Zidovudine related impurity C, Lamivudine, salicylic acid, Zidovudine and Zidovudine related impurity B in fixed oral dosage tablets over the concentration ranges of 0.0204 mg/mL-0.0088 mg/mL, 0.0962 mg/mL-0.7699 mg/mL, 0.1929 mg/mL-1.5410 mg/mL and 0.0088 mg/mL-0.024 mg/mL respectively. The Correlation Coefficient (r2) for Zidovudine related impurity C, Lamivudine, salicylic acid, Zidovudine and Zidovudine related impurity B were greater than 0.998. The LOD were found to be between 1.9x10-4 mg/mL to 2.69 x10-4 mg/mL.  The proposed method is precise, specific, accurate and robust for the simultaneous estimation of Zidovudine related impurity C, Lamivudine, salicylic acid, Zidovudine, Zidovudine related impurity B and other related impurities in dosage forms. Keywords: Zidovudine related impurity C, Lamivudine, salicylic acid, Zidovudine, Zidovudine related impurity B, Lamivudine related impurities, Zidovudine related impurities RP-HPLC, Validation.

Relative Response Factor for Lamivudine and Zidovudine Related substances by RP-HPLC with DAD detection

A study was conducted to establish the Relative Response Factors for Zidovudine related impurity C, Lamivudine salicylic acid and Zidovudine related impurity B.  A simple and fast isocratic Reverse Phase High Performance Liquid Chromatography (RP-HPLC) method was used for the simultaneous determination of the related impurities. The method consists of a mobile phase combination of Acetonitrile (HPLC grade) and Buffer (0.0680 g of Potassium Dihydrogen Orthophosphate, 0.3 ml of Triethylamine, pH adjusted to 8.0 with Orthophosphoric acid to a final volume preparation of 100 ml) in the ratio 10:90 using Phenomenex Luna 5-µm C18 (2)-250 x 4.6-mm, 5-µm) as a stationary phase, flow rate of 1.0 mL/min with detection at 270 nm. The RRF for Zidovudine related impurity C, Lamivudine salicylic acid and Zidovudine related impurity B were 2.07, 0.13 and 1.28 respectively.   Results obtained for quantification of the related substance in lamivudine and zidovudine single dose oral solid dosage form using the RRF and know standards shows no significant difference at 95 % confidence interval. The RRF can therefore be used for the quantification of know related impurities in lamivudine zidovudine oral dosage form using the stated chromatographic conditions

Pneumococcal capsular polysaccharide immunity in the elderly.

Immunity against pneumococcal infections is impaired in older people, and current vaccines are poorly protective against pneumococcal disease in this population. Naturally-acquired immunity against pneumococcal capsular polysaccharides develops during childhood and is robust in young adults, but deteriorates with advanced age. In particular, antibody levels and function are reduced in older people. Pneumococcal vaccines are recommended for people over 65 years of age. However, the benefits of polysaccharide and protein-conjugated vaccines in this population are small, due to both serotype replacement and incomplete protection against vaccine-serotype pneumococcal disease. In this review we overview the immune mechanisms by which naturally-acquired and vaccine-induced pneumococcal capsular polysaccharide immunity declines with age, including altered colonization dynamics, reduced opsonic activity of antibodies (particularly IgM) and impaired mucosal immunity

A critical role of T follicular helper cells in human mucosal anti-influenza response that can be enhanced by immunological adjuvant CpG-DNA

T Follicular helper cells (TFH) are considered critical for B cell antibody response, and recent efforts have focused on promoting TFH in order to enhance vaccine efficacy. We studied the frequency and function of TFH in nasopharynx-associated lymphoid tissues (NALT) from children and adults, and its role in anti-influenza antibody response following stimulation by a live-attenuated influenza vaccine (LAIV) or an inactivated seasonal virus antigen (sH1N1). We further studied whether CpG-DNA promotes TFH and by which enhances anti-influenza response. We showed NALT from children aged 1.5-10 years contained abundant TFH, suggesting efficient priming of TFH during early childhood. Stimulation by LAIV induced a marked increase in TFH that correlated with a strong production of anti-hemagglutinin (HA) IgA/IgG/IgM antibodies in tonsillar cells. Stimulation by the inactivated sH1N1 antigen induced a small increase in TFH which was markedly enhanced by CpG-DNA, accompanied by enhanced anti-HA antibody responses. In B cell co-culture experiment, anti-HA responses were only seen in the presence of TFH, and addition of plasmacytoid dendritic cell to TFH-B cell co-culture enhanced the TFH-mediated antibody production following CpG-DNA and sH1N1 antigen stimulation. Induction of TFH differentiation from naïve T cells was also shown following the stimulation. Our results support a critical role of TFH in human mucosal anti-influenza antibody response. Use of an adjuvant such as CpG-DNA that has the capacity to promote TFH by which to enhance antigen-induced antibody responses in NALT tissue may have important implications for future vaccination strategies against respiratory pathogens

Hypothermia and Fever After Organophosphorus Poisoning in Humans—A Prospective Case Series

There have been many animal studies on the effects of organophosphorus pesticide (OP) poisoning on thermoregulation with inconsistent results. There have been no prospective human studies. Our aim was to document the changes in body temperature with OP poisoning. A prospective study was conducted in a rural hospital in Polonnaruwa, Sri Lanka. We collected data on sequential patients with OP poisoning and analyzed 12 patients selected from 53 presentations who had overt signs and symptoms of OP poisoning and who had not received atropine prior to arrival. All patients subsequently received specific management with atropine and/or pralidoxime and general supportive care. Tympanic temperature, ambient temperature, heart rate, and clinical examination and interventions were recorded prospectively throughout their hospitalization. Initial hypothermia as low as 32°C was observed in untreated patients. Tympanic temperature increased over time from an early hypothermia (<35°C in 6/12 patients) to later fever (7/12 patients >38°C at some later point). While some of the late high temperatures occurred in the setting of marked tachycardia, it was also apparent that in some cases fever was not accompanied by tachycardia, making excessive atropine or severe infection an unlikely explanation for all the fevers. In humans, OP poisoning causes an initial hypothermia, and this is followed by a period of normal to high body temperature. Atropine and respiratory complications may contribute to fever but do not account for all cases

PCV13 induced IgG responses in serum associate with serotype-specific IgG in the lung

Pneumococcal conjugate vaccine efficacy is lower for non-invasive pneumonia than invasive disease. In this study, participants were vaccinated with PCV13 or HepA (control). Bronchoalveolar lavage samples were taken between 2-6 months and serum at 4- and 7-weeks post vaccination. In the lung, anti-capsular IgG levels were higher in the PCV13 group compared to control for all serotypes, except 3 and 6B. Systemically, IgG levels were elevated in the PCV group at 4-weeks for all serotypes, except 3. IgG in BAL and serum positively correlated for nearly all serotypes. PCV13 shows poor immunogenicity to serotype 3, implying lack of protective efficacy. Clinical trial registration with ISRCTN: 4534043