there was an article in the Phil Inquirer where local docs were asking why the dept of health wouldn't approve of a newer Dengue vaccine.
A previous flawed dengue vaccine killed a few kids here in the Philippines and caused a big scandal here.
now Dengue is important to me: we have lots of cases, including a few kids who died of it in our area. And I had a complicated case 15 months ago and still haven't recovered my strength.
So would a vaccine have protected me? And what about the new vaccines? they seem to have a fairly good protection rate (80 percent in some) but what about complications: either at the time of the immunization or if you do manage to get an infection with Dengue (with the Dengvaxia vaccine, if the kid got dengue he got a complicated case)
So I did research and put the stuff on my medical blog so I could read it slowly later on my tablet.
and today I got a popup saying the latest Grok was open for questions.
So I asked about does the attenuated Dengue vaccine induce immunological problems
the answer:
Key Points
Yes, the attenuated dengue vaccine can cause immunological problems, especially antibody-dependent enhancement (ADE) in some people.
ADE can make dengue more severe if the person gets infected after vaccination and wasn't previously exposed to dengue. This risk is mainly with vaccines like Dengvaxia, but may vary by vaccine type.
Overview The attenuated dengue vaccine, such as Dengvaxia, is designed to protect against dengue by using a weakened form of the virus. However, it can lead to immunological issues, particularly in people who haven't had dengue before. This is due to a process called antibody-dependent enhancement (ADE), where the vaccine might make a future dengue infection worse instead of better. This is surprising because vaccines are typically expected to only protect, not potentially harm in certain cases.
It's important to know your dengue exposure history before getting vaccinated, as it affects the safety and effectiveness.
Details for Consideration Who Is Affected?
The risk of ADE is higher in individuals who were not previously infected with dengue and receive the vaccine, then later get infected. For those already exposed to dengue, the vaccine is generally safe and effective.
What Is ADE? ADE happens when antibodies from the vaccine help the virus enter cells more easily, potentially leading to more severe disease if the person gets dengue later. This is a known concern with live attenuated dengue vaccines. Other Vaccines: Another attenuated vaccine, TAK-003, shows promise with fewer ADE issues, but more research is needed to confirm this.
The specific vaccine matters for safety.
Comprehensive Analysis of Attenuated Dengue Vaccine and Immunological Impacts This section provides a detailed examination of the attenuated dengue vaccine, focusing on its potential to induce immunological problems, with a particular emphasis on antibody-dependent enhancement (ADE) and other related concerns. The analysis is grounded in extensive web-based research, including clinical trial data, regulatory approvals, and scientific literature, to ensure a thorough understanding for healthcare professionals, researchers, and informed laypersons.
Background on Attenuated Dengue Vaccines
Attenuated dengue vaccines use live, weakened forms of the dengue virus to stimulate an immune response without causing the full disease. Notable examples include Dengvaxia (CYD-TDV) by Sanofi Pasteur and TAK-003 by Takeda. Dengvaxia, a live recombinant tetravalent vaccine, was the first licensed dengue vaccine, approved in various countries since 2015, while TAK-003, also live-attenuated, received approval in the European Union in 2022 and other regions like Indonesia (Takeda's QDENGA Approval). These vaccines aim to protect against all four dengue virus serotypes (DENV-1, DENV-2, DENV-3, DENV-4), which is crucial given the global burden of dengue, affecting an estimated 390 million people annually (Dengue Vaccines Update).
Immunological Problems:
Focus on Antibody-Dependent Enhancement (ADE)
One significant immunological problem associated with attenuated dengue vaccines is ADE, a phenomenon where non-neutralizing or sub-neutralizing antibodies facilitate viral entry into cells via Fcγ receptors, potentially increasing viral replication and disease severity. This is particularly noted with Dengvaxia. Research indicates that Dengvaxia can sensitize dengue-naïve recipients to severe dengue upon subsequent natural infection, leading to restricted FDA approval in 2019 for use only in individuals with prior laboratory-confirmed dengue infection (FDA Dengvaxia Approval). This restriction arose from concerns that vaccination without prior exposure could worsen outcomes, as seen in the Philippines in 2017, where over 733,000 children were vaccinated regardless of serostatus, leading to controversy due to increased severe dengue cases (Dengue Vaccine Wikipedia).
ADE is linked to the vaccine eliciting cross-reactive antibodies against the pre-membrane (prM) and fusion loop epitope (FLE) of DENV, which are not fully neutralizing and can enhance infection in later exposures (Antibody-Dependent Enhancement Challenge). This risk is higher in baseline seronegative individuals, with studies showing increased hospitalization rates for dengue type 3 among vaccinated seronegative participants in some trials (New Dengue Vaccine Efficacy).
Comparative Analysis: Dengvaxia vs. TAK-003 While Dengvaxia has clear ADE concerns, TAK-003 appears to have a different safety profile. Clinical trials, such as the phase 3 efficacy study (NCT02747927), suggest TAK-003 is efficacious against symptomatic dengue over three years, with no significant ADE issues reported in the literature reviewed (Three-Year Efficacy TAK-003). However, the general concern about ADE with live attenuated vaccines remains, and long-term data are still being evaluated.
TAK-003's approval in Indonesia without pre-vaccination testing suggests a broader application, but U.S. approval was withdrawn in 2023 due to data collection disagreements with the FDA, indicating ongoing scrutiny (Takeda Withdrawal BLA).
Other Potential Immunological Issues Beyond ADE,
the survey of side effects for Dengvaxia includes common reactions like headache, injection site pain, and fever, with rare severe allergic reactions reported (Dengvaxia Side Effects). There is no strong evidence from the searches linking attenuated dengue vaccines directly to autoimmune disorders, despite dengue infection itself being associated with autoimmune features in case reports (Autoimmune Features Dengue).
General vaccine safety literature suggests that while vaccines can theoretically trigger autoimmune diseases, epidemiological studies do not support this for systemic autoimmune diseases, and no specific cases were found for dengue vaccines (Vaccinations and Autoimmune Diseases).
Clinical Implications and Recommendations
The immunological problems, particularly ADE, necessitate careful screening for prior dengue exposure before vaccination with vaccines like Dengvaxia. The CDC recommends Dengvaxia for children aged 9–16 years with laboratory-confirmed previous dengue infection living in endemic areas, highlighting the importance of serostatus (CDC Dengue Vaccine). For TAK-003, while initial data suggest fewer ADE concerns, ongoing surveillance is crucial, especially given its recent approvals and the need for long-term efficacy and safety data.
Summary Table of Vaccine Characteristics and ADE Risk Vaccine Type Approval Status ADE Risk in Seronegative Common Side Effects Dengvaxia Live Recombinant Tetravalent Approved in US, EU, etc. High Headache, injection site pain, fever TAK-003 Live-Attenuated Tetravalent Approved in EU, Indonesia Low (Preliminary Data) Viral upper respiratory infection, etc. This table summarizes key attributes, aiding in understanding the differential immunological risks.
Conclusion In conclusion, attenuated dengue vaccines, particularly Dengvaxia, can induce immunological problems, with ADE being the most significant, especially in dengue-naïve individuals. This risk underscores the importance of pre-vaccination screening. TAK-003 shows promise with potentially lower ADE risks, but further research is needed. Healthcare providers should consider individual serostatus and vaccine type to mitigate these immunological challenges.
Key Citations Dengvaxia European Medicines Agency Takeda's QDENGA Approval Dengue Vaccines Update FDA Dengvaxia Approval Dengue Vaccine Wikipedia New Dengue Vaccine Efficacy Three-Year Efficacy TAK-003 Takeda Withdrawal BLA Antibody-Dependent Enhancement Challenge Dengvaxia Side Effects Autoimmune Features Dengue Vaccinations and Autoimmune Diseases CDC Dengue Vaccine
my impression: Grok found the articles and summaries that took me four hours of reading and research. If I have time, I will compare it's conclusions to my own conclusions.
And it shows value for research, and is so easy that even great grandmoms can use it.
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