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7/15

Self test

    Below are some actions that you should consider for the investigation and control of this disease cluster.

    For each action, select one of the following responses.

Before you answer, consider the following-

  • What if any, further information you would require in order to come to a decision?

  • What is the time frame for the action?

  • Could improved isolate resolution beyond serogroup help, bearing in mind that two cases (4 and 5) were PCR-confirmed so there is no isolate?

Communicate with health professionals to cascade clear guidance and with the University and the wider public to explain the situation, dispel any myths and to describe risks and actions

A) Would take this action regardless
B) Would not take this action
C) May take this action based on understanding of the relationship between meningococcal strains
Communications should go through an agreed communications lead to ensure consistent and up to date messages are being given out. As you do not currently know how strains are related you will need to explain this in your communications.
Try again
Waiting for more detailed information should not prevent initial communications from taking place
Genomics would provide more detailed information, and could rule in or out direct transmission between various cases in this scenario. However genomic information may be challenging to interpret and explain

Consider extending prophylaxis to the whole University (15,000 students and 1070 staff)

A) Would take this action regardless
B) Would not take this action
C) May take this action based on understanding of the relationship between meningococcal strains
Given the severity of the disease, the fact that two students have died and that the onset of symptoms can be very rapid, there may be grounds for this course of action. This does involve a substantial number of people and would take significant resources to organise and implement. The decision should also take into account the level of concern in the University and the town and the level of engagement of the university authorities
Guidance in institutional outbreaks of meningococcal disease states that “If two confirmed/probable cases who attend the same preschool group, school, college or university arise within a four-week period and are, or could be, caused by the same serogroup, public health action is indicated that may involve prophylaxis of a wider group than close contacts of each case. It is not necessary to wait for microbiological results on probable cases (high immediate risk of further cases)”

This describes the current situation; on day 22, there have been 4 cases of serogroup C disease among students of the same University.

If you choose not to offer prophylaxis to the whole university, you should have a clear rationale for selecting those who ARE offered prophylaxis.

Genomics would provide an improved understanding of the relationship between the available isolates. If there is clear evidence that all cases were caused by highly related strains (ie evidence of direct transmission) then wider prophylaxis might be pursued. Genomics could also rule out linkage between some or all strains and could provide evidence on which to base a more focussed prophylaxis strategy.

Identify links of remote cases 1 and 2 to the university and extend chemoprophylaxis to individuals identifiable within the social network linking the distant cases to the University

A) Would take this action regardless
B) Would not take this action
C) May take this action based on understanding of the relationship between meningococcal strains
Without specific close links of remote cases to the university, active follow up of geographically distant cases where a link was found during routine public health follow up is not usual.

Genomics could provide information that can rule out linkage between two strains, thereby negating the need for further epidemiological investigation and public health action for unrelated cases. Such information is likely ot help communications and health advice to the community in the areas where the remote cases occurred.

Conversely, genome sequence analysis could confirm transmission of highly related strains between cases where there is no obvious epidemiological link – indicating closer review

The resolution of whole genome sequencing means that it may be possible to provide evidence regarding the direction of transmission. The availability of genomic information raises questions, if two previously unrelated cases are shown (in real time investigations) to be related by virtue of their genome sequence – what actions would this lead to? If the direction of transmission were apparent to investigators, what does this mean for the public health management?

Although additional follow up for all remote cases is not usual, it may be wise to assess the relatedness of the isolates and consider follow up should the information support the cases being part of a common transmission network. Not taking wider linkage could mean not identifying potential source (s) of infection outside your local area and could also prolong a disease outbreak by failing to identify potential carriers and provide prophylaxis to prevent infection or onward transmission to others.

Resources used to pursue wider linkage could be used to concentrate on controlling the University cluster.

Genomics could provide information that can rule out linkage between two strains, thereby negating the need for further epidemiological investigation and public health action for unrelated cases. Or conversely could confirm transmission of highly related strains between cases where there is no obvious epidemiological link.

Knowing this information prior to undertaking wider investigations may help you to target your efforts.

However, The resolution of whole genome sequencing means that it may be possible to provide evidence regarding the direction of transmission. The availability of genomic information raises questions, if two previously unrelated cases are shown (in real time investigations) to be related by virtue of their genome sequence – what actions would this lead to? If the direction of transmission were apparent to investigators, what does this mean for the public health management?

Perform investigations that could inform management of future outbreaks and give more detailed information on the current situation (above that required to control spread and prevent further cases), this might include swabbing close contacts of cases, swabbing the wider student population, collecting serum from cases and / or contacts

A) Would take this action regardless
B) Would not take this action
C) May take this action based on understanding of the relationship between meningococcal strains
This action would commit resources above and beyond those needed to control spread prevent further cases, however liaising with other partners such as microbiology, immunisation and academic colleagues – a robust protocol could be developed in order to investigate the situation and provide evidence that could help manage such outbreaks in the future and could provide samples to aid research efforts for meningococcal disease
This action would commit resources above and beyond those needed to control spread prevent further cases, so may be considered beyond the immediate remit.

However not taking this type of action would mean not taking the chance to gain a deeper understanding of disease transmission.

Using genomics to identify relationships between disease causing strains could provide information on which to base a more focussed research question. Extending this approach to carriage strains identified among contacts and the wider university could help provide context for the disease causing strains.

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