Blog and Opinion
Wednesday 17th May 2023
Combating West Nile Virus (WNV)- The NEJM leads with a perspective that WNV requires a consideration for revisiting vaccination or at least continued development of these.
As the article is from authors based in the US then naturally the references refer to the increases in reported infections and deaths in humas in southern states as well as the impact on farming through bovine cases. This is another arbovirus, vectored by mosquitoes of both night and daytime flying species (Culex and Aedes). WNV is widely distributed across other continents such as Africa, Middle East, West Asia, SE Asia and Europe.
In Europe the European Center for Disease Control (ECDC) has a specialist surveillance unit for WNV, and subsequent vectors. The latest seasonal surveillance from 2021 showed 159 cases acquired within EU member states. Although this number is small and not of any epidemic size the first reported case was in 2015 and constantly reported at over 100 cases per year.
These reported cases are geographically reported include southern France, Northern Italy, Greece, and Eastern Europe. With reported outbreaks of Dengue (France 2022) and Tick-Borne Encephalitis (UK 2023) the vector patterns are extending due to a variety of reasons that include climate warming, increased traffic movement post Covid and changes in wild bird distribution patterns. When comparing this with animal and veterinary reports a clear geographical overlap in areas becomes apparent.
This raises the question currently should the EK and also EU states be concerned about WNV to the extent of the USA. Probably not as the infection rates are not comparable. Therefore, do we need to support the development of a WNV vaccine? Probably yes as climate warming continues the seasons in Europe will become warmer and move further north in latitude, indicating at some time in the future the need of a vaccine will be required. When will this be needed is reflected in the recording of data, the ECDC only started with data collection in 2015; whilst the Americans first recorded this is 1999. However, the impact and cost is shown with the 3000+ hospitalisations in California between 2004 and 2017, the average hospital cost was $59.9 million per year.
The argument then rises which new arbovirus takes precedent for development funding. Currently we have on trial malaria vaccines in Africa and new licences for dengue and chikungunya vaccines by US, UK, and EU authorities, does WNV need to be added to the equation?
Monday 30th January 2023
With the new calendar year comes the reviews of the risks from infections and reports that make consolidated reading for 2023. At the head of the reports are those diseases transmitted by the arboviruses and their expected impact in countries for 2023. Already the medical authorities from Thailand are expecting 3-4 times increase in dengue infections in 2023 compared to 2022 and 100% increase in chikungunya infections. In 2022 the malaria from Plasmodium knowlesi appeared in the islands of SE Asia around Thailand.
As the predictions and to some affect results are recognised by the destination countries are the departing countries travel health practitioners as aware and have products and information readily available?
Already we have little cholera vaccine available in the UK for travellers, but we still have travellers going to at risk destinations and the question again arises, are travel health practitioners increasing their advice and sales of preventative products to align with this?
The subjective and maybe realistic answer is probably not. The question as to why could be due to several influencing factors from historically not being a high priority discussion; unaware of the level of risk; not indicated on national reference websites.
With arboviruses not being treatable with anti-viral medication, the release of a dengue vaccine that requires 2 doses – at 0 and 3 months outside, of many pretravel consultations period, the emphasis again comes back onto raising the awareness of the need to take personal protection more seriously then before.
16th November 2022
New Dengue vaccine
We all welcome the introduction of the new dengue vaccine Qdenga by Takeda. This vaccine is ahead of its counterparts by providing cover across all 4 serotypes of the virus without the need for a positive confirmatory dengue test before vaccination.
This is heralded as a new vaccine and is likely to be available in the UK some time in 2023. Qdenga will no doubt be offering this vaccine to both travellers and also to residents in the affected countries.
This is where the situation will need some management as the schedule for Qdenga is two doses 3 months apart. In communities where the population is resident, the return for the second vaccine can be provided and managed easily. However, this is very different to the traveller community who frequently attend travel clinics for vaccinations in less than 4 weeks before travel. The consideration of a 0–3-month schedule is not available to them and with more backpackers travelling for 2 months or longer to infected areas then the risk becomes significantly high.
Then this leads to the question of how much protection could be afforded from the first (and possibly the only) dose of Qdenga. The Medical Information department informs me that from the trial data just over 80% protection is awarded from the first dose. The question then arises of how significant is this protection level to an at-risk traveller? By comparison we know that tick borne encephalitis can provide protection levels of 90%, 14 days after a second dose; and Ixiaro produces around 97% after second dose at 7 days.
With continuing rises in global temperatures, we are already experiencing mosquito borne infections in previously unseen area. So far this year we have what is becoming an annual report of infection in the Florida. South-Eastern Asian countries such as Vietnam, Nepal, Philippines are weekly reporting increased levels of infection in tens of thousands with levels greater than 100% from previous years.
The idea of a new vaccine is very much welcomed for the residents of these communities. However, with the increase in global travel and the spread of the mosquito vector there is a justified level of risk from partially or unvaccinated travellers visiting these countries. Perhaps this is a call-out to any new vaccine manufacturer; consider all of the opportunities and communities when designing trial methods and not rely on a singular response or answer to a sole healthcare patient sub-group.
27th October 2022
It’s not just about the vaccination
In the recent article appearing in The Pharmacist there is a candid report of the reporter receiving a flu vaccination at her local pharmacy. Although the clinical delivery of the service appeared to be successful the management of the appointment fell short of expected standards.
Currently all healthcare providers are subject to workforce pressures, and this is felt across both private and public sectors. The use of support staff is becoming a more vital role in the management of the system and the availability of the correct technology to streamline the service provision.
But how is this communicated and what are the backup systems when IT goes down, a patient forgets their registration details or does not use or have access to IT. When policies are written for mass-vaccination campaigns and large volume of recipients – a simple one-fix fits all, does not work, and several other scenarios need to be worked out, planned for and supporting staff need to be familiar with their use.
Without this planning on a service the end-user, the patient, is less likely to want to be vaccinated next year, adding to the impact of decreasing vaccination rates and missing herd immunity levels. So, the cycle of lower vaccination uptake, increasing infection and more treatments can be reduced by investing time into a public health plan that looks at the entire process and plans for the non-conforming patients and has pathways to resolve their issues.
Why do we not see a reduction in rabies following WHO advice?
Following the recent report in the BMJ (https://www.bmj.com/content/378/bmj.o2284.full) citing high profile rabies deaths in India, it suggests that reduction and eventual eradication is unlikely unless a series of different strategies can be applied together.
The article highlights issues that are not unique to India and exist elsewhere in the world and although the WHO has suggested the principles to be considered, there needs to be a link with the reality of the provision of public health in that community.
Items to be considered on the global agenda
1.Vaccine efficacy and production- India is the largest vaccine manufacturer in the world, do they have and how effective is the quality control within the assembly and manufacturing. Who, how and when are vaccines tested and how are counterfeits products dealt with under legislation.
2.The WHO lists an international strategy to vaccine all animals and reduce the number of stray dogs. Easier said than done in countries where the cost of veterinary treatment is high and not considered a priority unless the animal is ill.
3.Availability of Rabies Immunoglobulin (RIG) difficult and expensive to mass-manufacture but an essential part of post-exposure treatment. Alternative methods now include the use of much cheaper but as effective monoclonal antibodies, yet these are not regularly used despite being supported by WHO.
4.Education of wound management- the increased washing time for a wound using soap and water is a proven step in reducing the risk of rabies infection. This is probably the lowest cost measure but requires a co-ordinated public health campaign to raise the awareness and effectiveness.
5.The WHO estimates there are up to 60000 deaths a year and several million bites associated to rabies. In areas with low reporting associated with high levels of risk then the accuracy of reporting does need to be questioned. Would an incentive for accurate reporting and recording of rabies exposures be a method to establish a true picture of the levels of global rabies.
In summary the ideas and some of the products are available already to reduce the number of reported deaths. However national and local governments through public health and health ministries need to scrutinise the surveillance and reporting measures to obtain a true picture and demand of treatment resources.
(Author notes- comments this week)
New Malaria vaccine
Recently the new malaria vaccine developed by University of Oxford and supported by Gavi/WHO has been published in clinical and social media. It is heralded as a significant breakthrough in the development of an effective vaccine form the trial data, achieving a 77% effectiveness rate, exceeding the WHO minimum of 77%.
Bothe the Lancet Infectious Diseases and the Independent Nurse highlight this vaccine as a world-changing potential to save lives. We are well aware that WHO consider the eradication of global malaria to be a priority by 2030.
Looking at the information that we have to hand is that the study was conducted at phase 2 only in a single country with a cohort of several hundred patients. The vaccine has multiple doses in its schedule with an unknown longevity or booster periods. When expanding these limitations to other countries where there is less control of the data how does the lack of compliance factor into the successes of the vaccine. We are all aware of the nomadic lifestyle in some countries and the reduced public health infrastructure in others. This is raising the question of how this vaccine campaign will be reasonably distributed across a continent with so many health inequalities to achieve the global eradication.
Whereas clinically the vaccine is effective in protecting against malaria, the euphoria of this breakthrough needs to be balanced with the continuing issues of compliance to a multiple vaccination schedule, access and availability in the attempt to reach the 2030 target.
(Author notes- comments this week)
Awareness of non-vaccinable diseases
With the remainder of countries recovering from Covid-19 infections and isolation the desire for tourism to support the economy is so necessary. In many lower income countries, the annual budgets set aside for public health services to spray properties and reduce insect populations were used for the management of Covid-services.
As a consequence, we have rising levels of insect borne infections such as dengue, chikungunya and Zika across these countries. This is expanded with climate changes and the warming of areas further and north and south than previously detected. We now have reports of Aedes species of mosquitoes across southern Europe and north into the UK. This has led to the establishment of a monitoring service at the ECDC of the West Nile virus which is transmitted by the same mosquitoes that carry dengue.
The response to this, is that insect repellents against these disease bearing mosquitoes will need to become as part of the protection as sunblock when visiting southern European destinations. This in turn will require the travel health practitioner to be as accurate and active as possible in the reminder to use insect repellents that appear on the WHO list of tested and approved preparations, such as DEET, picaridin (Saltidin), and oil of lemon eucalyptus.