A propagated chickenpox outbreak in a composite elementary school is written up in this HS340 Unit 6 example, from case definition and epidemic curve to attack rates by vaccine doses. Searches like "hs 340 unit 6 assignment example", "hs340 unit 6 sample" and "hs340 unit 6 example" land here.
What a finished HS340 Unit 6 outbreak investigation writeup looks like
Styled as a health department field summary, the writeup runs about five pages. Notification comes first: the school nurse reported three rash illnesses in one classroom within a week. A boxed case definition follows, written to include mild breakthrough disease, since vaccinated children often develop fewer than 50 lesions, many of them never blistering. The epidemic curve plots onset in three-day intervals across 48 days and shows four clusters: the index case, then 8 cases, 18 cases and a final 6, each wave roughly one incubation period after the last. An attack rate table by vaccination status comes next: 11 of 24 unvaccinated students fell ill, 5 of 48 with one dose and 17 of 468 with two, for estimated effectiveness of 77 and 92 percent. Control measures and limitations close the summary.
How a HS340 Unit 6 example is structured
The writeup follows the investigation's logic rather than the calendar. The case definition leads, after a line on verification, because it decides who appears on the curve, and a definition requiring blisters would have dropped most vaccinated cases. The curve comes next and carries the central inference. Its repeated peaks, spaced about two weeks apart, fit varicella's incubation of roughly 14 to 16 days and rule out a single shared exposure, so the investigation looks for chains of contact instead of a source. The attack rate table tests the obvious question about vaccine failure and answers it with rates, not anecdotes: most cases were vaccinated simply because most students were. Control measures are then matched to the propagated pattern, with exclusion until lesions crust and vaccination of students missing a dose. Limitations close the report.
A definition wide enough for mild cases
An acute generalized rash without another apparent cause, in a student or staff member, with onset inside the outbreak window. Confirmed cases need laboratory evidence or a link to another case; the rest are probable.
Four waves on one curve
Three-day bins across 48 days, onset dates along the horizontal axis and case counts up the vertical. The caption names the pattern as propagated and marks the date of the vaccination clinic.
Attack rates by doses received
Unvaccinated students fell ill at 45.8 percent, one-dose students at 10.4 and two-dose students at 3.6. The table converts those rates into effectiveness estimates and flags that small groups make them imprecise.
Why most cases were vaccinated
Seventeen of 33 cases had two doses, which sounds alarming until the denominators appear. With 468 of 540 students fully vaccinated, even a highly effective vaccine leaves the largest count of cases in that group.
Breakthrough disease described
Fourteen of the 17 two-dose cases had fewer than 50 lesions. The writeup notes that mild cases still transmit and that missing them would have made the curve end too early.
Exclusion, catch-up doses and limits
Exclusion until all lesions crust, a school clinic offering doses to children missing one, and notices to families of pregnant or immunocompromised students. Limits include onset dates reported by parents.
Where marks go in HS340 Unit 6
Outbreak rubrics in HS340 commonly split credit four ways: how cases were defined, how the curve was drawn and read, what the attack rates show, and whether the control plan fits the agent. Definition marks here depend on person, place and time plus a clinical description that captures mild breakthrough cases; a definition written for classic blistering chickenpox loses credit because it would undercount the very children an investigator most needs to find. Curve marks require bins that fit the agent and an interpretation of shape, and the example names the propagated pattern and ties the wave spacing to incubation. Attack rates with denominators by vaccine status earn the analysis row. The usual deductions follow a curve read as a single exposure, vaccine failure claimed from case counts alone, and control measures borrowed from a foodborne scenario.
Get a HS340 Unit 6 example written to your instructions
Share the scenario, line list or onset dates from the HS340 Unit 6 assignment, plus the directions and rubric. Back comes a free first custom sample in 24-48 hours, with a case definition fitted to the agent, a curve binned to its incubation, and attack rates calculated for whatever groups the data can support.
HS340 Unit 6 questions, answered
How does the writeup tell a propagated outbreak from a point-source one?
By the curve's shape and spacing. A single shared exposure produces one peak whose width reflects the range of incubation times. Spread from person to person produces successive peaks roughly one incubation period apart, often growing before control measures take hold. The chickenpox curve shows four clusters spaced about two weeks apart, which is why the writeup looks for chains of contact.
Is it fair to estimate vaccine effectiveness from one school?
As an illustration, yes, with the imprecision stated. The attack rate among unvaccinated children rests on only 24 students, so a few cases more or fewer would move the estimate noticeably. The writeup reports 77 and 92 percent as rough figures and notes that published effectiveness comes from larger studies. What the table establishes firmly is that vaccinated children fell ill far less often.
Should the case definition include laboratory confirmation?
It should allow for it without requiring it. Most outbreak cases are classified through clinical findings and links to other cases, because testing every child is rarely practical. The example uses a two-tier definition, confirmed with laboratory evidence or an epidemiologic link and probable otherwise, and reports both tiers on the curve so a reader can see how many rest on each.