Evaluating the efficiency of specimen pooling for PCR-based detection of COVID-19

In the age of a pandemic, such as the ongoing one caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the world faces a limited supply of tests, personal protective equipment, and factories and supply chains are struggling to meet the growing demands. This study aimed to evaluate the efficacy of specimen pooling for testing of SARS-CoV-2 virus, to determine whether costs and resource savings could be achieved without impacting the sensitivity of the testing. Ten previously tested nasopharyngeal and throat swab specimens by real-time polymerase chain reaction (PCR), were pooled for testing, containing either one or two known positive specimens of varying viral concentrations. Specimen pooling did not affect the sensitivity of detecting SARS-CoV-2 when the PCR cycle threshold (Ct) of original specimen was lower than 35. In specimens with low viral load (Ct > 35), 2 of 15 pools (13.3%) were false negative. Pooling specimens to test for Coronavirus Disease 2019 infection in low prevalence (≤1%) areas or in low risk populations can dramatically decrease the resource burden on laboratory operations by up to 80%. This paves the way for large-scale population screening, allowing for assured policy decisions by governmental bodies to ease lockdown restrictions in areas with a low incidence of infection, or with lower-risk populations.     

Limited and Short-Lasting Virus Neutralizing Titers Induced by Inactivated SARS-CoV-2 Vaccine

In vitro determination of severe acute respiratory syndrome coronavirus 2 neutralizing antibodies induced in serum samples from recipients of the CoronaVac vaccine showed a short protection period against the original virus strain and limited protection against variants of concern. These data provide support for vaccine boosters, especially variants of concern circulate.     

Laser tattoo removal in Thai students

Objective

To review the results of laser tattoo removal in Thai students.

Material and methods

This is a retrospective review study of the students participating in our tattoo removal program at Srakaew Province, Thailand. The laser used was a 1064 nm Q-switched Nd:YAG laser (spot size: 3 mm, pulse duration: 6 ns, fluence: 3.5–7.5 J/cm²). A maximum of 5 laser treatments per student was performed at 2-month intervals.The data collected included age and sex of the students and information regarding the tattoos (time of tattoo existence, person who performed the tattoo procedure, method and price of tattooing, number of tattoo figures, complications during and after tattoo procedure including cleaning methods of tattoo needle) and the laser procedure (laser parameters, pain level during laser removal assessed by pain score sheet, treatment results, complications, side effects). Correlations were analyzed between the person who did the tattoo and complications after laser tattoo removal procedure, the age of tattoo and results of laser treatment and complications, and between the pain level and the time of EMLA^® application.

Results

The 115 students involved were aged between 8 years 4 months and 19 years 11 months. The mean time of tattoo existence was 1.9 ± 1.2 years. The majority of the students were tattooed (1) by amateur practitioners and (2) by hand. The costs of tattoo procedure ranged between 0 and 118 Thai Bahts. Friends influenced the students in favor of tattooing, and both the home and school were popular places for the tattooing procedure to take place. Ankles and fingers were the most common sites for students’ tattoos. A clinical clearance of 76–100% was achieved in 75% of the treated tattoos. Observed side effects were mild to moderate. Textural changes, hyperpigmentation, hypopigmentation, and scarring occurred in 41%, 3%, 3% and 17% of the cases, respectively. There was no statistically significant correlation between EMLA^® application time and the pain score. There was also no correlation between the person who did the tattoo, or the age of tattoo to the complications or side effects after laser tattoo removal.

Conclusion

The students were influenced and had tattoos by persons familiar to them, mostly at places which they often attended, including temples and schools. The students were not primarily concerned about the social consequence of having tattoos. Laser tattoo removal by means of a Q-switched Nd:YAG laser could clinically clear tattoos in 75% of the cases. However, there were side effects, such as hypopigmentation, hyperpigmentation and scarring.     

Hematologic and clinical indices of malaria in a semi-immune population of western Thailand

This study examines hematologic profiles of persons with acute Plasmodium falciparum or P. vivax infection in Maesod on Thailand's western border with Myanmar compared with febrile, non-parasitemic persons also reporting to malaria clinics. Nine hundred seventy-nine subjects were malaria-negative, 414 were infected with P. falciparum, and 646 were infected with P. vivax. Persons with patent parasitemia tended to have significantly lower white blood cell, red blood cell, platelet, and hemoglobin levels than those who were malaria-negative. For the first time, a parallel trend in thrombocytopenia with parasitemia was found to be associated with both P. falciparum, and P. vivax infection. Using logistic regression, persons with platelet counts < 150,000/microL were 12-15 times more likely to have malaria than persons with platelet counts > or = 150,000/microL. This study supplements previous literature on the hematologic effects of malaria and helps define those alterations for a semi-immune population. Thrombocytopenia is identified as a key indicator of malaria in these febrile patients.     

A growing global network's role in outbreak response: AFHSC-GEIS 2008-2009

A cornerstone of effective disease surveillance programs comprises the early identification of infectious threats and the subsequent rapid response to prevent further spread. Effectively identifying, tracking and responding to these threats is often difficult and requires international cooperation due to the rapidity with which diseases cross national borders and spread throughout the global community as a result of travel and migration by humans and animals. From Oct.1, 2008 to Sept. 30, 2009, the United States Department of Defense's (DoD) Armed Forces Health Surveillance Center Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) identified 76 outbreaks in 53 countries. Emerging infectious disease outbreaks were identified by the global network and included a wide spectrum of support activities in collaboration with host country partners, several of which were in direct support of the World Health Organization's (WHO) International Health Regulations (IHR) (2005). The network also supported military forces around the world affected by the novel influenza A/H1N1 pandemic of 2009. With IHR (2005) as the guiding framework for action, the AFHSC-GEIS network of international partners and overseas research laboratories continues to develop into a far-reaching system for identifying, analyzing and responding to emerging disease threats.     

Randomized,Double-Blind,Placebo-Controlled Clinical Trial of a Two-Day Regimen of Dihydroartemisinin-Piperaquine for Malaria Prevention Halted for Concern over Prolonged Corrected QT Interval

Dihydroartemisinin-piperaquine, the current first-line drug for uncomplicated malaria caused by Plasmodium falciparum and Plasmodium vivax in Cambodia, was previously shown to be of benefit as malaria chemoprophylaxis when administered as a monthly 3-day regimen. We sought to evaluate the protective efficacy of a compressed monthly 2-day treatment course in the Royal Cambodian Armed Forces. The safety and efficacy of a monthly 2-day dosing regimen of dihydroartemisinin-piperaquine were evaluated in a two-arm, randomized, double-blind, placebo-controlled cohort study with 2:1 treatment allocation. Healthy military volunteers in areas along the Thai-Cambodian border where there is a high risk of malaria were administered two consecutive daily doses of 180 mg dihydroartemisinin and 1,440 mg piperaquine within 30 min to 3 h of a meal once per month for a planned 4-month period with periodic electrocardiographic and pharmacokinetic assessment. The study was halted after only 6 weeks (69 of 231 projected volunteers enrolled) when four volunteers met a prespecified cardiac safety endpoint of QTcF (Fridericia''s formula for correct QT interval) prolongation of >500 ms. The pharmacodynamic effect on the surface electrocardiogram (ECG) peaked approximately 4 h after piperaquine dosing and lasted 4 to 8 h. Unblinded review by the data safety monitoring board revealed mean QTcF prolongation of 46 ms over placebo at the maximum concentration of drug in serum (C_max) on day 2. Given that dihydroartemisinin-piperaquine is one of the few remaining effective antimalarial agents in Cambodia, compressed 2-day treatment courses of dihydroartemisinin-piperaquine are best avoided until the clinical significance of these findings are more thoroughly evaluated. Because ECG monitoring is often unavailable in areas where malaria is endemic, repolarization risk could be mitigated by using conventional 3-day regimens, fasting, and avoidance of repeated dosing or coadministration with other QT-prolonging medications. (This study has been registered at ClinicalTrials.gov under registration no. {"type":"clinical-trial","attrs":{"text":"NCT01624337","term_id":"NCT01624337"}}NCT01624337.)     

Ex Vivo Drug Susceptibility Testing and Molecular Profiling of Clinical Plasmodium falciparum Isolates from Cambodia from 2008 to 2013 Suggest Emerging Piperaquine Resistance

Cambodia''s first-line artemisinin combination therapy, dihydroartemisinin-piperaquine (DHA-PPQ), is no longer sufficiently curative against multidrug-resistant Plasmodium falciparum malaria at some Thai-Cambodian border regions. We report recent (2008 to 2013) drug resistance trends in 753 isolates from northern, western, and southern Cambodia by surveying for ex vivo drug susceptibility and molecular drug resistance markers to guide the selection of an effective alternative to DHA-PPQ. Over the last 3 study years, PPQ susceptibility declined dramatically (geomean 50% inhibitory concentration [IC₅₀] increased from 12.8 to 29.6 nM), while mefloquine (MQ) sensitivity doubled (67.1 to 26 nM) in northern Cambodia. These changes in drug susceptibility were significantly associated with a decreased prevalence of P. falciparum multidrug resistance 1 gene (Pfmdr1) multiple copy isolates and coincided with the timing of replacing artesunate-mefloquine (AS-MQ) with DHA-PPQ as the first-line therapy. Widespread chloroquine resistance was suggested by all isolates being of the P. falciparum chloroquine resistance transporter gene CVIET haplotype. Nearly all isolates collected from the most recent years had P. falciparum kelch13 mutations, indicative of artemisinin resistance. Ex vivo bioassay measurements of antimalarial activity in plasma indicated 20% of patients recently took antimalarials, and their plasma had activity (median of 49.8 nM DHA equivalents) suggestive of substantial in vivo drug pressure. Overall, our findings suggest DHA-PPQ failures are associated with emerging PPQ resistance in a background of artemisinin resistance. The observed connection between drug policy changes and significant reduction in PPQ susceptibility with mitigation of MQ resistance supports reintroduction of AS-MQ, in conjunction with monitoring of the P. falciparum mdr1 copy number, as a stop-gap measure in areas of DHA-PPQ failure.     

Effective treatment of uncomplicated Plasmodium falciparum malaria with azithromycin-quinine combinations: a randomized, dose-ranging study

Azithromycin, the most potent antimalarial macrolide antibiotic, is synergistic with quinine against Plasmodium falciparum in vitro. We assessed combinations of azithromycin and quinine against uncomplicated P. falciparum malaria at the Armed Forces Research Institute of Medical Sciences-Kwai River Clinical Center along the Thailand-Myanmar border, an area with a high prevalence of multidrug-resistant P. falciparum. Four regimens were assessed in an open-label dose-ranging design involving 61 volunteers. All received oral quinine (Q; 30 mg/kg/day divided every 8 hours for 3 days) with oral azithromycin (Az; 500 mg twice a day for 3 days, 500 mg twice a day for 5 days, or 500 mg three times a day for 3 days). A comparator group received quinine and doxycycline (Dx; 100 mg twice a day for 7 days). Study observation was 28 days per protocol. Sixty volunteers completed the study. Seven days of QDx cured 100% of the volunteers. One failure occurred in the lowest QAz regimen (on day 28) and none occurred in either of the two higher Az regimens. Cinchonism occurred in nearly all subjects. Overall, the azithromycin regimens were well tolerated, and no volunteers discontinued therapy. Three- and five-day azithromycin-quinine combination therapy appears safe, well tolerated, and effective in curing drug-resistant P. falciparum malaria. Further evaluation, especially in pediatric and obstetric populations, is warranted.