From an email written April 14th 2011 by the FMD international expert on vaccination in the field, Dr Simon Barteling, (See below)
... It is clear that a"Vaccination to Live" (VTL) policy seems not as easy to implement as one may think.
To make it more feasible I would like to add a"risk assessment" approach.
Considering risk assessment elements and considering situations of awareness (like in the EU) one could also think of adapting export rules to the severe ness of the outbreaks and to the number of vaccinated cattle surviving at 3 months after the last FMD case.
Fact is that millions of vaccinated cattle, surviving outbreaks, never have caused recurrent outbreaks. However, others might state that a million cattle are difficult to cover in all aspects of control, surveillance, and testing.
The other way around, one could propose that control either by slaughter or by vaccination only could have the same consequences for export if the number of vaccinated cattle (and small ruminants?) surviving at 3 months is limited and e.g. less than 100.000 (and holdings have been screened for carriers). Accordingly, one could propose between 100.000 to 200.000 four months and 200.000 to 400.000 five month and above 400.000 six months after the last FMD case..
There seems space for negotiations e.g. to go to somewhat lower (or higher) numbers. Anyhow, where in the past millions of vaccinated cattle never have caused recurrent FMD the survival of 100.000 cattle only will mean at least an additional significant reduction of an already very small risk, left apart the application of the DIVA principle.
Nowadays all vaccines for vaccine banks are purified and don’t raise antibodies against non-structural proteins. In Brazil and Argentina all vaccines are purified as well. Several validated tests to screen for such antibodies - to trace vaccinated carriers – are on the market.
The system also represents a premium principle. In a country where there is high awareness one will detect the FMD at an early stage and one will rapidly take action. The number of cattle to be vaccinated - and to be screened - will remain relatively low.
Milk can be sterilized by UHT-treatment. Would it make sense if during the 3-4 months waiting period slaughter of vaccinated animals is forbidden? During that period there will be a ban on transport of animals anyhow. Then, after that period everything can go back to normal.
I hope these considerations in addition to the"points to consider" will contribute to a different approach of the control of FMD outbreaks.
Control and eradication of foot-and-mouth disease: Paul Sutmoller (Animal Health Consultant, former chief of Laboratories of the Panamerican Foot and Mouth Disease Center PAHO/WHO), Simon S. Barteling (Consultant Veterinary Vaccines, former Head Department FMD Vaccine Development, and Production ID-Lelystad and former Head Community Co-ordinating Institute), Raul Casas Olascoaga (Direct Advisor of the Minister of Livestock, Agriculture and Fisheries, Uruguay, former Director of the Panamerican Foot and Mouth Disease Center PAHO/WHO), Keith J. Sumption (Lecturer in International Animal Health, Centre for Tropical Veterinary Medicine, University of Edinburgh), Virus Research 91 (2003) 101-144.
Culling vs. vaccination: challenging a dogma in veterinary (FMD) science:
Outbreaks of FMD can either be controlled by stamping-out or (circle) culling, or by (ring-) vaccination around the outbreak area, or by a combination of the two methods. The pros and cons of the two methods are discussed. A major draw-back – next to many other disadvantages - of the massive circle culling is its contribution to spreading disease. We challenge the dogma that "vaccination against FMD will prevent the symptoms but will not eradicate the disease". Where outbreaks were controlled by consistent vaccination with a qualified vaccine the disease did not re-occur. Also, there are no documented cases where cattle vaccinated with a qualified vaccine, caused new outbreaks. Therefore, the risks posed by vaccinated carriers must be an acceptable, "close to zero" risk. Certainly, if used in combination with an anti-NSP test, vaccination should become the major tool in controlling outbreaks of FMD, without additional negative consequences for export trade.