Vaccinated individuals might represent a
Vaccinated individuals might represent a safer source of hyperimmune serum. Two vaccine candidates will be tested soon in west Africa. If serum from vaccinated individuals has neutralising activity against the virus in cell models, this serum could be used as adjuvant therapy for EVD. In parallel, animal models could be developed to compare hyperimmune serum against a placebo. In the current scenario, this strategy could offer some hope to patients with this devastating disease.
Romulus Breban and colleagues (September issue) present modelling results of hepatitis C virus (HCV) interventions in Egypt. They suggest focusing interventions on people who regularly receive medical injections to achieve the greatest epidemiological effect on HCV transmission. However, we believe that universal treatment at 2·5 or even 15 years after infection (as presented in figure 5) is highly ambitious, as it would necessitate immediate identification and treatment of most of the people living with hepatitis C in Egypt. This process would demand substantial resources and the removal of many practical barriers. Although the proposed treatment coverage of the core group seems to be achievable, we would like to see the focused intervention analysed with more realistic general levels of treatment coverage to guide operational implementation. Breban and colleagues previously reported that the prevalence of HCV in people younger than 50 years in Egypt fell substantially between 1996 and 2004. This finding implies the HCV-infected The stability is ageing and that age is highly important in the progression of the epidemic, affecting future prevalence and thus continuing transmission. Decreasing prevalence is supported by evidence of falling HCV seroprevalence among blood donors, from 17·7% in 2000 to 7·6% in 2007. In Breban and colleagues\' modelling analysis, incidence was estimated from earlier data (2001–06) and age effects were excluded. As a result, the basic reproduction numbers calculated by Breban and colleagues might be overestimates, suggesting that less ambitious interventions might be sufficient to control the HCV epidemic.
We agree with James Jansson and David Wilson that universal treatment for hepatitis C virus (HCV) infection in Egypt is an ambitious public health strategy. This fact has been part of the motivation for our work. In our study, we identified that most HCV transmission in Egypt is caused by a core group of individuals undergoing frequent medical injections. The existing national treatment strategy does not target these individuals, who are thus treated in the same proportions as the general population, leading to only a small reduction in the basic reproduction number (R; from 3·54 to 3·03). However, individuals in this core group could be easily targeted with testing, prevention counselling, and treatment, as they identify themselves by accessing health care. Such targeted interventions could lead to a substantial reduction in R and, most importantly, HCV incidence. The origins of the HCV epidemic in Egypt are attributed to mass campaigns of parenteral anti-schistosomal therapy between the 1960s and the 1980s. Once these mass campaigns stopped, HCV transmission variables (key variables included in our model were frequency of medical injections, probability of reuse of injecting material, and infection probability by injection) decreased substantially. It is reasonable to assume that, since R depends strongly on these variables, R decreased substantially as well. However, HCV continued to be transmitted, to a lesser extent, through everyday medical procedures. Hepatitis C has a very long chronic period, resulting in a very slowly evolving epidemic. A steady reduction in HCV prevalence in Egypt suggests that transmission in the era since mass parenteral anti-schistosomal therapy is insufficient to maintain the HCV prevalence reached in the late 1980s. However, a falling prevalence does not imply that HCV transmission variables and, implicitly, R, saw further substantial decreases since the end of the mass campaigns. The only notable subsequent event, leading to further decrease in the R of the HCV epidemic in Egypt, might be the initiation of the present national strategy against the disease.