Publications by authors named "Raviprakash K"

The development of a safe and effective vaccine to protect against COVID-19 is a global priority due to the current high SARS-CoV-2 infection rate. Currently, there are over 160 SARS-CoV-2 vaccine candidates at the clinical or pre-clinical stages of development. Of these, there are only three whole-virus vaccine candidates produced using β-propiolactone or formalin inactivation.

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Introduction And Background: A tetravalent DNA vaccine for Dengue virus is under development but has not yet achieved optimal immunogenicity. Salivary glands vaccination has been reported efficacious in rodents and dogs. We report on a pilot study testing the salivary gland as a platform for a Dengue DNA vaccine in a non-human primate model.

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Dengue fever, caused by dengue viruses (DENV 1-4) is a leading cause of illness and death in the tropics and subtropics. Therefore, an effective vaccine is urgently needed. Currently, the only available licensed dengue vaccine is a chimeric live attenuated vaccine that shows varying efficacy depending on serotype, age and baseline DENV serostatus.

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Article Synopsis
  • A study was conducted to test the effectiveness of high-titre anti-influenza plasma versus low-titre plasma in treating severe influenza A infections, as previous research lacked rigorous trial design.
  • The randomized, double-blind phase 3 trial involved 41 medical centers in the US and included both children and adults with confirmed influenza A, assessing outcomes over a 28-day period.
  • The main goal was to evaluate clinical status after 7 days using a six-point scale that categorized patients from death to full recovery, ensuring unbiased results by masking treatment assignments to all participants.
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Phase 1 clinical trials with a DNA vaccine for dengue demonstrated that the vaccine is safe and well tolerated, however it produced less than optimal humoral immune responses. To determine if the immunogenicity of the tetravalent dengue DNA vaccine could be enhanced, we explored alternate, yet to be tested, methods of vaccine administration in non-human primates. Animals were vaccinated on days 0, 28 and 91 with either a low (1 mg) or high (5 mg) dose of vaccine by the intradermal or intramuscular route, using either needle-free injection or electroporation devices.

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Objective: To describe an outbreak of influenza A in an oncology unit, highlighting infection control methods implemented, and examining reasons health care workers (HCWs) present to work with influenza-like illness (ILI).

Methods: Confirmed cases were defined by the presence of ILI and a positive nasopharyngeal polymerase chain reaction swab for influenza A H3. Probable cases were defined as exposed HCWs with ILI who were unavailable for polymerase chain reaction testing.

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Article Synopsis
  • The study investigates how different blood collection methods and anticoagulants affect the results of hemagglutination-inhibition (HAI) assays used to measure the effectiveness of influenza vaccines.
  • Researchers collected blood samples from 30 donors using six types of tubes, comparing serum and various anticoagulated plasma samples against three influenza viruses.
  • Results show HAI and microneutralization (MN) titers are consistent across most collection methods for type A viruses, but type B virus titers vary more significantly, particularly with EDTA plasma samples.
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We conducted an open label, dose escalation Phase 1 clinical trial of a tetravalent dengue DNA vaccine (TVDV) formulated in Vaxfectin to assess safety and immunogenicity. A total of 40 dengue- and flavivirus-naive volunteers received either low-dose (1 mg) TVDV alone ( = 10, group 1), low-dose TVDV (1 mg) formulated in Vaxfectin ( = 10, group 2), or high-dose TVDV (2 mg, group 3) formulated in Vaxfectin ( = 20). Subjects were immunized intramuscularly with three doses on a 0-, 30-, 90-day schedule and monitored.

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Background: Middle East respiratory syndrome (MERS) is a severe respiratory illness with an overall mortality of 35%. There is no licensed or proven treatment. Passive immunotherapy approaches are being developed to prevent and treat several human medical conditions where alternative therapeutic options are absent.

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This study describes an antibody-dependent NK cell degranulation assay, as a biomarker to assess antibody-dependent cellular cytotoxicity (ADCC) response in influenza plasma and for antibody therapies against influenza infection. The concentration of neutralizing antibodies (NAbs) against the hemagglutinin receptor of influenza viruses is a current determinant in protection against infection, particularly following receipt of the seasonal influenza vaccine. However, this is a limited assessment of protection, because: (i) NAb titers that incur full protection vary; and (ii) NAb titers do not account for the entire breadth of antibody responses against viral infection.

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Background: Influenza causes substantial morbidity and mortality despite available treatments. Anecdotal reports suggest that plasma with high antibody titres to influenza might be of benefit in the treatment of severe influenza.

Methods: In this randomised, open-label, multicentre, phase 2 trial, 29 academic medical centres in the USA assessed the safety and efficacy of anti-influenza plasma with haemagglutination inhibition antibody titres of 1:80 or more to the infecting strain.

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Venezuelan equine encephalitis virus (VEEV) is a mosquito-borne RNA virus that causes low mortality but high morbidity rates in humans. In addition to natural outbreaks, there is the potential for exposure to VEEV via aerosolized virus particles. There are currently no FDA-licensed vaccines or antiviral therapies for VEEV.

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The promise of DNA vaccines is as compelling today as it was more than a decade ago. Ease of manufacture, stability at ambient temperatures without the need for a cold chain and its ability to mimic natural infections and elicit appropriate immune responses makes this vaccine platform extremely attractive. Although, human clinical trials of DNA vaccines have yielded less than optimal results, the approval and licensing of a few veterinary vaccines is testimony to the proof-of-concept and the hope that licensed DNA vaccines for human use may not be too far away.

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We explored the feasibility of collecting convalescent plasma for passive immunotherapy of Middle East respiratory syndrome coronavirus (MERS-CoV) infection by using ELISA to screen serum samples from 443 potential plasma donors: 196 patients with suspected or laboratory-confirmed MERS-CoV infection, 230 healthcare workers, and 17 household contacts exposed to MERS-CoV. ELISA-reactive samples were further tested by indirect fluorescent antibody and microneutralization assays. Of the 443 tested samples, 12 (2.

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As of 13 November 2015, 1618 laboratory-confirmed human cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection, including 579 deaths, had been reported to the World Health Organization. No specific preventive or therapeutic agent of proven value against MERS-CoV is currently available. Public Health England and the International Severe Acute Respiratory and Emerging Infection Consortium identified passive immunotherapy with neutralizing antibodies as a treatment approach that warrants priority study.

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Since the early 1990s, DNA immunization has been used as a platform for developing a tetravalent dengue vaccine in response to the high priority need for protecting military personnel deployed to dengue endemic regions of the world. Several approaches have been explored ranging from naked DNA immunization to the use of live virus vectors to deliver the targeted genes for expression. Pre-clinical animal studies were largely successful in generating anti-dengue cellular and humoral immune responses that were protective either completely or partially against challenge with live dengue virus.

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Background: In outbreak settings, mass vaccination strategies could maximize health protection of military personnel. Self-administration of live attenuated influenza vaccine (LAIV) may be a means to vaccinate large numbers of people and achieve deployment readiness while sparing the use of human resources.

Methods: A phase IV, open-label, randomized controlled trial evaluating the immunogenicity and acceptance of self-administered (SA) LAIV was conducted from 2012 to 2014.

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Four distinct serotypes of dengue viruses (DENV) are the cause of re-emerging dengue fever (DF) and dengue hemorrhagic fever (DHF). Dengue circulation in the Caribbean has gone from none or single serotype to multiple serotypes co-circulating with reports of continuing cycles of progressively more severe disease in the region. Few studies have investigated dengue on Sint Eustatius.

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Middle East respiratory syndrome coronavirus (MERS-CoV) is the etiologic agent of a highly lethal pneumonia. Here, we report the full-genome sequence of the Jordan-N3/2012 strain after serial passage in two distinct mammalian cell lines. The genome exhibits noteworthy stability, which may inform the development of vaccines and therapeutics used to treat infection with this virus.

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Dengue is the most important arbovirus worldwide and is the virus that causes dengue fever and the more severe dengue hemorrhagic fever. There are four serotypes of dengue with each possessing the ability to cause disease. Developing a preventive vaccine is the most efficient and effective way to prevent these diseases, and because immunity to one serotype does not protect against the other serotypes, a vaccine must provide tetravalent protection.

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Two novel methods of dengue virus inactivation using iodonaphthyl azide (INA) and aminomethyl trioxsalen (AMT) were compared with traditional virus inactivation by formaldehyde. The AMT inactivated dengue-2 virus retained its binding to a panel of 5 monoclonal antibodies specific for dengue-2 envelope protein, whereas inactivation by formaldehyde and INA led to 30-50% decrease in binding. All three inactivated viruses elicited high level virus neutralizing antibodies in vaccinated mice.

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A tetravalent DNA vaccine formulated with Vaxfectin adjuvant was shown to elicit high levels of neutralizing antibody against all four dengue virus serotypes (Porter et al., ( 16) ), warranting further testing in humans. In preparation for a phase 1 clinical testing, the vaccine and the adjuvant were manufactured under current good manufacturing practice guidelines.

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Background & Objectives: Structural interventions have the capacity to improve the outcomes of HIV/AIDS interventions by changing the social, economic, political or environmental factors that determine risk and vulnerability. Marginalized groups face disproportionate barriers to health, and sex workers are among those at highest risk of HIV in India. Evidence in India and globally has shown that sex workers face violence in many forms ranging from verbal, psychological and emotional abuse to economic extortion, physical and sexual violence and this is directly linked to lower levels of condom use and higher levels of sexually transmitted infections (STIs), the most critical determinants of HIV risk.

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A prototype dengue-1 DNA vaccine was shown to be safe and immunogenic in a previous Phase 1 clinical trial. Anti-dengue-1 neutralizing antibody responses were detectable only in the group of volunteers receiving the high dose of nonadjuvanted vaccine and the antibody titers were low. Vaxfectin(®), a lipid-based adjuvant, enhances the immunogenicity of DNA vaccines.

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Candidate dengue DNA vaccine constructs for each dengue serotype were developed by incorporating pre-membrane and envelope genes into a plasmid vector. A Phase 1 clinical trial was performed using the dengue virus serotype-1 (DENV-1) vaccine construct (D1ME(100)). The study was an open-label, dose-escalation, safety and immunogenicity trial involving 22 healthy flavivirus-naïve adults assigned to one of two groups.

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