21 Sep Dengue Can Outsmart Vaccines By Mutating When Patient Has Fever
MedicalResearch.com Interview with: [caption id="attachment_51442" align="alignleft" width="142"] Dr. Shee-Mei Lok[/caption]
Dr Shee-Mei Lok, PhD
Professor in the Emerging Infectious Disease program
Duke-NUS, a school of National University of Singapore
MedicalResearch.com: What is the background for this study?
Response: Dengue virus consists of four different serotypes (DENV1-4) and within each serotypes, there are multiple strains. In terms of the viral particle shape, our previous research work using some laboratory adapted strains showed these DENV2 strains are very interesting in that it can change shape from the smooth spherical surface particles when grown at mosquito physiological temperature (29oC) and then becomes bumpy surfaced particles when incubated at human physiological temperature (37oC). This ability to transform into different virus surface structures helps the virus to escape from the immune system of the human host. Hence understanding the mechanism of how this occur is important for therapeutics and vaccine development. Here we also identified a laboratory adapted virus strain that do not showed this structural changes.
[caption id="attachment_51443" align="alignleft" width="720"]
Micrographs of DENV2 with different distribution of smooth and bumpy surfaced particles when incubated at different temperatures to mimic the physiological temperature in the mosquitoes (29°C, left panel), human host (37°C, middle panel) and when humans are experiencing high fever (40°C, right panel). Colour gradient from blue to red shows the rise in temperature.Xin-Ni Lim, Emerging Infectious Diseases Programme, Duke-NUS Medical School[/caption] We showed some differences in their amino acid sequences and We showed some differences in their amino acid sequences and mutating these residues coupled with observing their surface structures showed which residues are important for this temperature induced structural change. Results showed that subtle mutations at different places on the envelope protein can destabilize the virus allowing them to change in structure when temperature is elevated. Due to the poor selection pressure of the artificial laboratory tissue culture system, gradual mutations of the virus is accumulated causing the virus to have bumpy surface morphology.
Prof. Satchi-Fainaro[/caption]
Prof. Ronit Satchi-Fainaro, PhD
Head, Cancer Research and Nanomedicine Laboratory
Department of Physiology and Pharmacology,
Sackler Faculty of Medicine,
Tel Aviv University,
Tel-Aviv 69978, Israel
[caption id="attachment_50670" align="alignleft" width="116"]
Prof. Florindo[/caption]
Prof. Helena Florindo, PhD
Head, BioNanoSciences – iMed.ULisboa
Faculty of Pharmacy,
University of Lisbon
Lisbon, Portugal
MedicalResearch.com: What are the main findings?
Response: The war against cancer in general, and melanoma in particular, has advanced over the years through a variety of treatment modalities, such as surgery, chemotherapy, radiation therapy and immunotherapy. The immune checkpoint inhibitors brought a breakthrough solution for advanced melanoma patients, but only a low percentage of those respond to this therapy, developing resistance and being affected by severe side effects. Despite the success of several vaccines against viral diseases, this success has not been materialized yet against cancer.
This study led by my lab at Tel Aviv University, and Helena Florindo’s lab at the University of Lisbon, describes the development of an effective nano-vaccine against melanoma, that also sensitizes the immune system to immunotherapies.
This nano-vaccine prevented melanoma, and also led to remarkable tumor inhibition and prolonged survival in mice already affected by this disease. 
Dr. Nandi[/caption]
Arindam Nandi PhD
Center for Disease Dynamics, Economics & Policy
MedicalResearch.com: What is the background for this study?
Response: The motivation for this study comes from a small but growing body of evidence on the potential long-term benefits of vaccines. The recent resurgence of measles outbreaks in several countries which had previously eliminated the virus makes our study additionally relevant. There have been over 1,000 measles cases reported across 28 states in the US so far in 2019, which is the largest number of cases the country has seen in almost 3 decades. Similarly high number of cases have been reported in several European countries in recent years. This study reiterates the importance of vaccination and proves the long-term benefits of the measles vaccine in low- and middle-income countries, which account for a large proportion of global measles cases.
Kathryn M. Edwards, M.D.
Sarah H. Sell and Cornelius Vanderbilt Chair in Pediatrics
Professor of Pediatrics
Vanderbilt University School of Medicine
Dr. Edwards discusses the statement from the Infectious Diseases Society of America (IDSA) regarding the Centers for Disease Control and Prevention’s new data on child vaccine rates across the United States.
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: To monitor the uptake of vaccines the CDC conducts a National Immunization Survey each year. This survey is conducted by random-digit dialing (cell phones or landlines) of parents and guardians of children 19-35 months of age. The interviewers ask the families who provides the vaccines for their children and if these providers can be contacted to inquire about the immunizations received. The overall response rate to the telephone survey was 26% and immunization records were provided on 54% of the children where permission was granted. Overall 15, 333 children had their immunization records reviewed.
When comparing immunization rates for 2017 and 2016, the last two years of the study, several new findings were discovered.
First the overall coverage rate for 3 doses of polio vaccine, one dose of MMR, 3 doses of Hepatitis b, and 1 dose of chickenpox vaccine was 90%, a high rate of coverage. Children were less likely to be up to date on the hepatitis A vaccine (70%) and rotavirus vaccine (73%). Coverage was lower for children living in rural areas when compared with urban areas and children living in rural areas had higher percentages of no vaccine receipt at all (1.9%) compared with those living in urban areas (1%).
There were more uninsured children in 2017 at 2.8% and these children had lower immunization rates. In fact 7.1% of the children with no insurance were totally unimmunized when compared with 0.8% unimmunized in those with private insurance. Vaccine coverage varies by state and by vaccine. 
