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News for 2011, January - Show latest items

Where are we with a malaria vaccine?


1. Our understanding
 
It would be great if nets were not needed and a vaccine, similar to that which proved so effective in the fight against polio, could be found.
 
Those who are most optimistic believe a vaccine may be available as early as 2015. However, many believe an effective vaccine is at least 15-20 years away, and even that may be optimistic. This is based on where we are with the most promising vaccine currently in trials and the number of years an approval process would take before a vaccine would be released for widespread use. 

So what is the most promising prospect at the moment? Progress has recently been announced with the 'experimental vaccine' RTS,S from GSK.[1] The results to date show 46% effectiveness (ie would protect 46 in every 100 people vaccinated) and protection lasts for 15 months[2].

Though the RTS,S vaccine meets the requirements of the Roll Back Malaria initiative's 2015 goal,[3] a vaccine that is only 50% effective cannot single-handedly turn back malaria. The polio vaccine has an effectiveness of 95%, and lasts a lifetime [4]. Until the malaria vaccine can achieve this degree of success, other interventions continue to be crucial.

Another obstacle to overcome is the difficulty storing and transferring a malaria vaccine to the locations where it is needed most. This process requires refrigeration, a problem that also faced polio vaccines so it is not insuperable, but it is costly. 

Our hope: scientists continue to make progress, and quickly.


2. Comments from Ally Olotu (in charge of GSK's RTS,S malaria vaccine programme at the Kemri-Wellcome Trust Research Programme)

"The efficacy we have seen in this study is in line with the targets set by the Malaria Vaccine Technology Roadmap and that it has a potential to save hundred of thousands of lives given the burden of the malaria disease in Africa. However I agree more work to improve on the efficacy of this and other malaria vaccines is required. This is currently ongoing with various groups.

A mechanism has been put in place by collaboration between local ministries of health, regulatory authorities, WHO and MVI at PATH to ensure that countries are able to make an informed decision on implementation of the RTS,S. This should avoid unnecessary delays. It may therefore take around 5 years or less from the outcome of phase III to implementation.

I agree with you that no single measure is enough to fight malaria. Should RTS,S be implemented, it would ideally be used as an addition to the existing measures, rather than as a sole intervention.
 
I agree vaccines have different sensitivities to heat and cold. However RTS,S  requires similar field cold chain conditions as current EPI vaccines as recommended by WHO (i.e temp 2-8C). Integration into EPI would therefore not be affected by cold chain conditions."

3. Further questions and responses

Rob: Am I correct in my understanding that 'RTS,S  requires similar field cold chain conditions as current EPI vaccines as recommended by WHO (i.e temp 2-8C).' means that the vaccine would need refrigeration?

Ally: Yes. But I wanted to point out that all EPI vaccines require refrigeration at one point in the cold chain and RTS,S would not require a separate system for delivery to the field. These systems are effective despite variation from country to country. The coverage for DPT vaccine for instance using this system is well over 75% in most African countries according to WHO report.

Rob: You comment 'A mechanism has been put in place by collaboration between local ministries of health, regulatory authorities, WHO and MVI at PATH to ensure that countries are able to make an informed decision on implementation of the RTS,S. This should avoid unnecessary delays. It may therefore take around 5 years or less from the outcome of phase III to implementation.' Can you let me know what the normal time period would be compressed to the 5 years and what elements are either shortened or missed out such that the 5 year timeframe can be achieved? Is this 5 years from today?

Ally: The registration of the vaccine will be done under EMEA article 58 (http://www.who.int/immunization_standards/vaccine_regulation/article_58/en/index.html). Under this plan, the file for the RTS,S vaccine candidate would be submitted to regulatory authorities in 2012 based on efficacy in children 5-17 months of age. Additional safety and immunogenicity data from the infant population will be submitted soon thereafter, followed by efficacy data for infants once available.

If all goes well the vaccine may get WHO recommendation in 2015, which is after the EMEA has reviewed the submitted file. Decision frame work for malaria vaccine was put in place in 2006 and is meant to address all the policy and programmatic issues before the countries are ready to make decision on malaria vaccine (http://www.malariavaccine.org/files/MVIfactsheet_DMF_091026.pdf). This process will definitely shorten the time to introduction which would normally take up to 15 years from the time vaccine is registered.

Rob: May I also ask your personal view on the possibility of a malaria vaccine being found that a) would have a 90% plus efficiency and/or b) a lifetime duration?

Ally: This is tough question to answer Rob. My personal view is more work is required to understand the immune correlates of protection against malaria in order to improve our ability to make more efficacious vaccines. It is amazing how much we still don't know about this meaning malaria vaccine development has largely been empirical. There is steady accumulation of knowledge on malaria immunity and hopefully this will inform the malaria Vaccinology research and lead to better vaccines.

I agree with you that 50% is not enough and more work is required to produce better vaccines. However given that hundreds of thousands of children are currently dying from this scourge each year it is very hard to justify throwing away something which could half that mortality and wait for better vaccine which is not yet on site.

Rob: Any view on the cost per dose (just the cost of the drug, not including delivered cost) – or who I can ask?

Ally: There is commitment from GSK and MVI to ensure that vaccine becomes available to those who need it. Efforts are ongoing to discuss on this possibility with malaria endemic countries and international institutions. The partners agree that price will not stand in the way of access, but it is too early to determine the exact price since the vaccine will not be submitted for initial regulatory review until 2012. Multilateral groups such as the GAVI Alliance, UNICEF and others will be involved in this collaboration to ensure vaccine are purchased in large volumes at affordable price once favorable recommendation is obtained from WHO and countries have made decision to introduce the vaccine.

I would direct you to David Poland of MVI for more information on the cost and delivery issues. MVI at PATH have funded the phase II RTS,S vaccine trials.


Targeted Distribution or Universal Coverage?


It is often difficult to decide where nets go when the need for nets far exceeds the quantity we can fund.

Should 20,000 nets go to one country or 10,000 each to two countries? The dilemma is the same whatever the number of nets involved. Some people somewhere will remain unprotected from malaria whatever the decision.

The choice is particularly stark when deciding whether to focus on those most at risk from malaria—children under five years old and pregnant women—or instead to achieve universal coverage, which means every sleeping space is covered in a (smaller) area.

A real example: There are 500 nets in total available for five villages. Each village contains 1,000 people, among whom are 100 pregnant women and children under five. Do you protect all the under fives and pregnant women in all five villages or blanket cover one village, given two people sleep under each net?

Each method has its benefits. 

The logic of protecting the most vulnerable is obvious: those most likely to contract malaria due to a less well-developed immune system (under fives) or weakened immune system (pregnant women) should be protected first. Their need is greatest and so they deserve our attention first.

The argument for universal coverage centres on the 'mass-effect' that occurs when 60% or more of sleeping spaces in a given area are covered. In such a circumstance, malaria rates fall dramatically because the pregnant female malaria-carrying mosquito population is denied its nightly blood meal. If these mosquitoes do not feed for 10-12 days they cannot reproduce. Fewer mosquitoes means fewer ways to get infected, which reduces the spread of malaria among net-users and non-net-users alike (see related links). 

The advantages of universal coverage come not only from preventing the pregnant female mosquito feeding, but also from the involvement and engagement of an entire community in malaria prevention. It can have a dramatic effect with malaria case rates falling precipitously.

There is no one answer.

In recent years, the move has been to universal coverage given the often dramatic effect on an entire community. The intention, using the example above, would then be to come back to the other villages as soon as possible and universally protect them too. While there are not enough funds for nets this is not always possible. In the meantime, difficult choices remain.
 
Relevant links

More milestones: 40,000th donor


We have just reached our 40,000th donor! A donor from Cardiff in Wales took us over the 40,000 mark and is now immortalised on our milestones page - thank you!

Incidentally, we have also gone past the 450,000th participant, or person involved in fundraising activities. Thanks to the Central Sports Masters Festival which took place in Japan.




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