Burden of Influenza-Associated Respiratory Hospitalizations, Vietnam, 2014-2016

Influenza burden estimates are essential to informing prevention and control policies. To complement recent influenza vaccine production capacity in Vietnam, we used acute respiratory infection (ARI) hospitalization data, severe acute respiratory infection (SARI) surveillance data, and provincial population data from 4 provinces representing Vietnam’s major regions during 2014–2016 to calculate provincial and national influenza-associated ARI and SARI hospitalization rates. We determined the proportion of ARI admissions meeting the World Health Organization SARI case definition through medical record review. The mean influenza-associated hospitalization rates per 100,000 population were 218 (95% uncertainty interval [UI] 197–238) for ARI and 134 (95% UI 119–149) for SARI. Influenza-associated SARI hospitalization rates per 100,000 population were highest among children <5 years of age (1,123; 95% UI 946–1,301) and adults >65 years of age (207; 95% UI 186–227), underscoring the need for prevention and control measures, such as vaccination, in these at-risk populations.

Acceptability of seasonal influenza vaccines among health care workers in Vietnam in 2017

INTRODUCTION

A demonstration project in Vietnam provided 11,000 doses of human seasonal influenza vaccine free of charge to healthcare workers (HCWs) in 4 provinces of Vietnam. Through this project, we conducted an acceptability survey to identify the main reasons that individuals chose to be vaccinated or not to inform and improve future immunization activities.

METHODS

We conducted a descriptive cross-sectional survey from May to August 2017 among HCWs at 13 selected health facilities. We employed logistic regression to determine the association between demographic and professional factors, and the decision to receive seasonal influenza vaccine. We performed post-hoc pairwise comparisons among reasons for and against vaccination using Chi square and Fisher's exact tests (for cell sizes <5).

RESULTS

A total of 1,450 HCWs participated in the survey, with a higher proportion of females than males (74% versus 26%). The median age of the participating HCWs was 35 years (median range 25.8-44.2). Among those surveyed, 700 (48%) HCWs were vaccinated against seasonal influenza during the first half of 2017. Younger HCWs under 30 and 30-39 years old were less likely to get vaccinated against seasonal influenza than HCWs ≥50 years old (OR = 0.5; 95%CI 0.4-0.8 and OR = 0.6; 95%CI 0.4-0.8 respectively). Nurses and other employees were more likely to get seasonal influenza vaccination than physicians (OR = 1.5; 95%CI 1.0-2.4 and OR = 2.0; 95%CI 1.2-3.2 respectively). The most common reason for accepting vaccination was fear of getting influenza (66%) and the most common reason for not getting vaccinated was concern about vaccine side effects (23%).

CONCLUSION

Acceptability of seasonal influenza vaccines in this setting varied among HCWs by age group and job category. Interventions to increase acceptance of vaccine among HCWs in this setting where influenza vaccine is being introduced free for the first time should include targeted risk communication on vaccine safety and efficacy.

Has the 2005 measles mortality reduction goal been achieved? A natural history modelling study

BACKGROUND

In 2002, the UN General Assembly Special Session on Children adopted a goal to reduce deaths owing to measles by half by the end of 2005, compared with 1999 estimates. We describe efforts and progress made towards this goal.

METHODS

We assessed trends in immunisation against measles on the basis of national implementation of the WHO/UNICEF comprehensive strategy for measles mortality reduction, and the provision of a second opportunity for measles immunisation. We used a natural history model to evaluate trends in mortality due to measles.

RESULTS

Between 1999 and 2005, according to our model mortality owing to measles was reduced by 60%, from an estimated 873,000 deaths (uncertainty bounds 634,000-1,140,000) in 1999 to 345,000 deaths (247,000-458,000) in 2005. The largest percentage reduction in estimated measles mortality during this period was in the western Pacific region (81%), followed by Africa (75%) and the eastern Mediterranean region (62%). Africa achieved the largest total reduction, contributing 72% of the global reduction in measles mortality. Nearly 7.5 million deaths from measles were prevented through immunisation between 1999 and 2005, with supplemental immunisation activities and improved routine immunisation accounting for 2.3 million of these prevented deaths.

INTERPRETATION

The achievement of the 2005 global measles mortality reduction goal is evidence of what can be accomplished for child survival in countries with high childhood mortality when safe, cost-effective, and affordable interventions are backed by country-level political commitment and an effective international partnership.

Accelerated measles control in the Western Pacific region

By the 1990s, an immunization program in the western Pacific had dramatically reduced measles morbidity and mortality. Building on the region's successful elimination of polio, several countries and areas achieved or are close to measles elimination, thus showing the potential for global eradication. The diverse challenges for measles control in different parts of the region have produced lessons that will help with future control, including the need for surveillance of sufficient standard to guide and monitor progress. A group of experts recognized both the potential and the challenges of the measles immunization program and proposed regional elimination as the appropriate disease control target for the region. No date was recommended for its achievement. If progress continues at the present rate, the western Pacific region should soon be able to set a target date for measles elimination.

Estimating the water solubilities of crystalline compounds from their chemical structures alone

Partial atomic charges are significant descriptors in predicting the water solubilities of crystalline organic compounds from their chemical structures. Lipophilicity remains the predominant factor. It was also found that quantitative estimates of hydrogen bond strengths (hydrogen bond factors) play important roles. These descriptors can be easily interpreted to guide chemists to the synthesis of compounds with increased or decreased water solubility. This work is based on a set of 22 compounds the aqueous solubilities of which were determined by a new potentiometric method, pSOL, and were confirmed, in part, by the traditional shake-flask method. A new software package, HYBOTPLUS, furnished the partial atomic charges and hydrogen bond factors.

Trends in prescriptions for highly active antiretroviral therapy in four New York City HIV clinics

OBJECTIVE

To describe trends in prescriptions for antiretroviral therapies and factors associated with prescriptions for highly active antiretroviral therapy (HAART).

METHODS

Medical records of patients at four HIV clinics in New York City were reviewed every 6 months. For the four 6-month periods 1997 to 1998, we identified patients with a CD4+ nadir <500 cells/microl; sample sizes were 434, 432, 503, and 643, respectively. Trends in HAART prescriptions were tested by logistic regression using robust variance estimates because some patients contributed more than one time period. Associations between HAART prescriptions and patient characteristics were tested by chi2 and multiple logistic regression analysis.

RESULTS

Patients were predominantly black or Hispanic (89%-90%) and male (66%-68%), and injection drug use was the most prevalent HIV risk (38%-49%). From 1997 to 1998, HAART prescriptions increased from 54% to 89% of antiretroviral prescriptions, and the proportion that included an nonnucleoside reverse transcriptase inhibitors (NNRTI) increased from 3% to 10%. HAART prescriptions were inversely associated with CD4+ nadir group during all time periods, and in the second half of 1998, patients with CD4+ nadir between 50 and 199 cells/microl were as likely to be prescribed HAART as the most immunosuppressed patients (CD4+ nadir <50 cells/microl; 91% versus 92%). HAART prescriptions were associated with clinic, HIV risk, and other patient characteristics in some time periods but not consistently.

CONCLUSIONS

In these four HIV clinics, prescriptions for HAART increased significantly from 1997 to 1998, leveling off at 89% in the second half of 1998. Increasingly, HAART was prescribed for healthier patients and included an NNRTI.

Outbreaks of salmonellosis associated with eating uncooked tomatoes: implications for public health. The Investigation Team

Laboratory-based surveillance of salmonella isolates serotyped at four state health departments (Illinois, Michigan, Minnesota and Wisconsin) led to the identification of multistate outbreaks of salmonella infections during 1990 (176 cases of S. javiana) and 1993 (100 cases of S. montevideo). Community-based case-control studies and product traceback implicated consumption of tomatoes from a single South Carolina tomato packer (Packer A) MOR 16.0; 95% CI2.1, 120.6; P < 0.0001 in 1990 and again in 1993 (MOR 5.7; 95 % CI 1.5, 21.9; P = 0.01) as the likely vehicle. Contamination likely occurred at the packing shed, where field grown tomatoes were dumped into a common water bath. These outbreaks represent part of a growing trend of large geographically dispersed outbreaks caused by sporadic or low-level contamination of widely distributed food items. Controlling contamination of agricultural commodities that are also ready-to-eat foods, particularly fruits and vegetables, presents a major challenge to industry, regulators and public health officials.

Quantitative structure-activity relationships among macrolide antibacterial agents: in vitro and in vivo potency against Pasteurella multocida

Quantitative structure-activity relationships have been found among macrolide antibacterial agents in their potencies against the bacterial pathogen Pasteurella multocida both in vitro and in mouse infections. To obtain these relationships we measured, among other things, the pK(a)'s and log P's of 15 known macrolides of diverse structures. Among these compounds, in vitro potency [log(1/MIC)] is a function of log P, log D, and CMR (R = 0.86). In vivo potency is a function of the higher pK(a), the HPLC chromatographic capacity factor log k', log(1/MIC) and pNF (R = 0.93). pNF is defined as the negative logarithm of the fraction of neutral drug molecules present in aqueous solution at pH 7.4. The same physical properties were determined for 14 macrolides not used in developing the original QSAR models. Using the in vivo model, we calculated the mouse protection potency ranges for these new compounds. Ten estimates agreed with those observed, three were lower by a half-order of magnitude, and one was calculated to be active in the range of 15-50 mg/kg, but in fact was not active at 50 mg/kg, the highest level tested. When these new compounds were combined with the original 15, and the QSAR's updated, the new equations for the in vitro and in vivo potencies were essentially the same as those originally found. Hence, the physical properties indicated above are major determinants of macrolide antibacterial potencies.

Repromicin derivatives with potent antibacterial activity against Pasteurella multocida

Reductive amination of repromicin with polyfunctional amines has led to new macrolide antibacterial agents, some of which are highly potent against the Gram-negative pathogen Pasteurella multocida both in vitro and in a mouse infection model. A key element in this discovery was the recognition that among certain known macrolides increasing lipophilicity results in diminished in vivo activity. One repromicin derivative, 20-[N-[3-(dimethylamino)-propyl]-N-L-alanylamino]-20-deoxorepro micin (35), was selected for advanced evaluation. At 5 mg/kg, a single subcutaneous dose was found to control induced pasteurellosis in swine and induced respiratory disease in cattle.

Anticoccidial activities of 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine and other alpha 2 adrenergic agonists

Activity against the coccidial pathogen Eimeria tenella in chickens has been discovered among alpha 2 adrenergic agonists. The clonidine analog 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine was active in feed at 7.5 ppm, a concentration similar to the use levels of potent commercial agents, e.g., maduramicin. Additional alpha 2 agonists were also found to have anticoccidial activity, for example, the catecholamine nordefrin, which is chemically unrelated to clonidine. However, alpha 1 agonists and alpha antagonists were inactive. These observations imply that anticoccidial effects reflect involvement of a receptor with the characteristics of the vertebrate alpha 2 adrenoceptor. alpha 2 agonists that permeate the blood-brain barrier (like clonidine) inhibit feed intake at efficacious levels, whereas those that are restricted to the peripheral compartment (such as catecholamines) do not inhibit feed intake as much. Hence, anticoccidial efficacy may be a peripheral adrenergic effect whereas depression of feed intake is likely centrally mediated.

Comparative molecular field analysis of anticoccidial triazines

Comparative molecular field analysis (CoMFA) of 2-(substituted phenyl)-1,2,4-triazine-3,5(2H,4H)-diones (triazines henceforth) resulted in an excellent correlation of their anticoccidial potencies with their physical properties. Two items about this work are notable: (i) the biological data are from a whole animal infectious disease model; and (ii) for the best results CoMFA required columns of measured "lipophilicity" and "acidity" data in addition to the calculated data in the steric field and electrostatic field columns. CoMFA resulted in a quantitative description of the major steric and electrostatic field effects, and gave significant new insights to factors governing potency. The model was used to "predict" the potencies of diverse triazines not used in making the model itself.

Further investigation of anticoccidial activity of 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine

The clonidine analog 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine exhibits potent activity against Eimeria tenella infections in chickens. Disease control was abrogated by a selective alpha 2 antagonist, which is consistent with the dependence of such activity upon binding to receptors with characteristics of the vertebrate alpha 2 adrenoceptor. Lack of significant activity against the parasite in tissue culture and our inability to detect significant binding of alpha 2 adrenergic ligands to E. tenella imply that the anticoccidial action may be an indirect effect mediated by the host. Efficacy varied, depending upon the Eimeria species, being greatest for the cecal species E. tenella and less for the intestinal species. The effects described differ substantially from previous accounts of adrenergic actions on parasitic protozoa. The evidence suggests that we have observed a new mechanism of action for antiparasitic drugs.

Linear discriminant and multiple regression analyses of anticoccidial triazines

Quantitative structure-activity relationships among some anticoccidial 2-(substituted-phenyl)-1,2,4-triazine-3,5-(2H,4H)-diones were studied by multiple regression analysis (MRA, the Hansch approach) and by linear discriminant analysis (LDA). With MRA the potencies of these compounds are correlated with their reverse-phase HPLC retention times and their 1H NMR chemical shifts at the 6-position. While the coefficients of the variable terms are significant, the moderate R2 (0.56) of the correlating equation suggests that predictions made from this analysis are not likely to be accurate. LDA supports the idea that these descriptors are related to potency, but the discriminant function does not lead to good classification. However, when coupled with a graphic display of the results, LDA gives a more immediate sense of the synthetic direction to take when seeking highly potent analogues. It is apparent that other important but not yet identified factors also play a role in determining the potencies of these compounds.

Novel degradation products from the treatment of salinomycin and narasin with formic acid

Salinomycin and narasin (4-methylsalinomycin) upon treatment with HCO2H furnish the known furanone fragment 3 and the complementary but rearranged fragments 1 and 2 respectively. The structure of 1 has been established by X-ray analysis. Upon being heated under reflux in PhMe, 1 undergoes the retrograde aldol reaction to furnish alpha, gamma-dimethyl-2-furanbutanal (4). The furan moiety of 1 is more resistant to electrophilic substitution than expected, but it can be acylated by highly reactive reagents such as (CF3CO)2O and AcOSO2Me. Compounds 1 and 2, the acetyl and trifluoracetyl derivatives of the former, and the reduction products thereof have no significant anticoccidial activity.

Cluster significance analysis contrasted with three other quantitative structure-activity relationship methods

Cluster significance analysis (CSA), a new statistical method to analyze structure-activity relationships in graphically displayed data, is contrasted with linear discriminant analysis, SIMCA, and the method of "relative odds". The data sets evaluated are as follows: antibacterial lasalocid derivatives, antimalarial naphthoquinones, and carcinogenic polycyclic aromatic hydrocarbons. CSA gives results comparable to these other methods, involves fewer assumptions, can be more reliable, and in general is easier to understand.

On the significance of clusters in the graphical display of structure-activity data

A method is presented to evaluate the statistical significance of an apparently clustered group in the graphical display of structure-activity data. Two variations are described; each is implemented by means of a computer program. The first is applicable in situations with relatively small sets of compounds where a complete enumeration of all possible clusters can be accomplished reasonably on a high-speed electronic computer. The second is applicable in cases where such a calculation would be too time consuming. This latter variation uses random sampling of the set of all possible clusters. An application for each variation is given: for the smaller case a reevaluation of a study on aminotetralin and aminoindan monoamine oxidase inhibitors; for the larger case the discovery of some physical parameters that influence mutagenicity among some aminoacridine derivatives. It is proposed that this new technique be called cluster significance analysis (CSA).

Side chain modifications in lankacidin group antibiotics

Novel N-acyl analogs of lankacidin may be prepared from 3-isocyanatolankone diformate [7,13-bis(formyloxy)-2-isocyanato-1,4,10,19-tetramethyl-16- oxabicyclo[13.2.2.]nonadeca-3,5,9,11-tetraen-17,18-dione]. Of seven such analogs evaluated in vitro only homolankacidin diformate showed significant activity. However, in a cell-free system two of the inactive analogs inhibited polypeptide synthesis as well as did lankacidin itself or erythromycin. Antibacterial activity, therefore, is a function of the ability of a congener to penetrate the bacterial cell membrane in addition to its intrinsic activity. Similarly, lankacidinol is as potent as lankacidin or erythromycin as an inhibitor of bacterial polypeptide synthesis in a cell-free system. This intrinsic activity is expressed as potent antibacterial activity against growing gram-positive cultures in O(2')-acyl derivatives with the proper lipophilicity.

The relationship between maternal and fetal plasma protein binding of methadone in the ewe during the third trimester

The binding of methadone to maternal and fetal plasma proteins was determined throughout the third trimester in the pregnant ewe. Blood was sampled from chronic indwelling catheters placed in the maternal aorta and fetal aorta. Methadone binding was determined by use of equilibrium dialysis with (3H)-methadone. Maternal binidng ranged from 50.4 to 89.5%, with a mean of 76.2 +/- 1.3 (SE)%. Fetal binding was initially significantly lower than maternal binding, but increased rapidly in the last two weeks before parturition. Prior to 130 days gestation, the ratio of fetal binding to maternal binding was 0.40 +/- 0.03. This binding ratio increased to 0.82 +/- 0.08 in the last few days of pregnancy. Preliminary results suggested that maternal binding was higher in the early post-partum period. These results demonstrate that the relationship between maternal and fetal plasma binding of methadone changes rapidly towards the end of pregnancy, and fetal binding approaches maternal binding at parturition.