Time Periods of Interest - HIV, STDs, Viral Hepatitis Flashcards
Define: Window Period
The time between when a person is exposed to a bacteria or virus and when a test can accurately detect organism.
Define: Incubation Period
The time elapsed between exposure to a bacteria or virus and when symptoms and signs are first apparent
HIV Window Period for Antibody Tests
23 to 90 Days.
This includes the Chembio SURE CHECK HIV Rapid Test
HIV Window Period for 4th Generation Test
18 to 45 days.
This test detects antigens, which are a part of the virus and present during acute HIV
HIV Window Period for Nucleic Acid Test
10 to 33 Days
What should an individual do if they are concerned about being exposed to HIV in the last 72 hours?
They should be referred to a health care provider immediately for post-exposure prophylaxis (PEP) evaluation
HIV Incubation Period
Within 2 to 4 weeks after infection.
People may experience a flu-like illness, lasting for a few weeks; these symptoms indicate an acute HIV infection.
Chlamydia NAAT Test Window Period
Window period for NAAT test is unknown but may range from 5 days up to 2 weeks.
The nucleic acid amplification tests are very sensitive and are able to detect a low number of organisms. Patients should be tested at time of visit.
If exposure was within 1 to 5 days, retesting two weeks after exposure would be recommended if more reassurance is needed.
Gonorrhea NAAT Test Window Period.
Window period for NAAT test is unknown but may range from 5 days up to 2 weeks.
The nucleic acid amplification tests are very sensitive and are able to detect a low number of organisms. Patients should be tested at time of visit.
If exposure was within 1 to 5 days, retesting two weeks after exposure would be recommended if more reassurance is needed.
Chlamydia (CT) Incubation Period
In patients who develop symptomatic infection, the incubation period is estimated to be 7 to 21 days
Gonorrhea (GC) Incubation Period
The incubation period ranges from 1 to 14 days, with most men becoming symptomatic within 2 to 5 days after exposure.
The incubation period in women is variable, but symptoms, when they do occur, usually develop within 10 days of exposure.
Time Period for Dual Therapy for Gonorrhea.
To be considered appropriately treated for GC, the Azithromycin and Ceftriaxone must be given on the same day.
Appropriate treatment also occurs if ceftriaxone is administered within 5 days after the azithromycin dose.
Patients are recommended to be retreated if they are given ceftriaxone in the clinic and don’t pick up their azithromycin from the pharmacy on that same day.
Chlamydia Retesting / Test of Cure
All individuals diagnosed with chlamydia should be retested 3 months after completing treatment.
Test of Cure:
Only recommended for pregnant women - 3 to 4 weeks after completing therapy
Gonorrhea Retesting / Test of Cure
All individuals diagnosed with Gonorrhea should be retested 3 months after completing treatment.
Test of Cure:
Recommended for individuals with pharyngeal gonorrhea treated with an alternative regimen 3 to 4 weeks after completing therapy
Syphilis Window Period
VDRL and RPR test results turn positive 1-2 weeks after chancre formation.
FTA-ABS and TP-PA are generally considered equally sensitive in the primary stage of disease.
Syphilis Incubation Period - Primary
The chancre typically occurs about 3 weeks (range 10 to 90 days) after exposure. The chancre lasts 3 to 6 weeks
Syphilis Incubation Period - Secondary
4 to 8 weeks after onset of primary chancre.
Syphilis Incubation Period - Tertiary Syphilis
1 to 20 years after exposure.
Syphilis Incubation Period - Early Neurosyphilis
Early forms of neurosyphilis usually occur a few months to a few years after initial infection
Syphilis Incubation Period - Ocular syphilis
Symptoms may develop at any stage
Hepatitis C - Window Period
HCV infection can be detected by anti-HCV (including HCV rapid tests) screening tests 4-10 weeks after infection.
Anti-HCV can be detected in >97% of people by 6 months after exposure.
HCV RNA can be detected as early as 2-3 weeks after infection
Hepatitis C - Window Period for Infants
The optimal timing of HCV RNA testing is unknown, but 2 to 6 months after birth is reasonable.
There is no value in repeated HCV RNA testing prior to 18 months of age. Anti-HCV testing should take place at or after 18 months of age.
If infants are positive for HCV RNA at 2-6 months of age, between 25% to 50% will spontaneously resolve HCV by 3 y ears old.
What is the overall risk of vertical transmission of Hepatitis C per pregnancy?
4 to 7 %
Hepatitis C - Incubation Period
In those people who do develop symptoms, the average period from exposure to symptom onset is 2-12 weeks (range: 2-26 weeks)
How long can HCV survive outside the body at room temperature?
Up to 3 weeks
How long can HCV survive in the barrel of a syringe?
Up to 63 days
Hepatitis B - Window Period
HBsAg will be detected an average of 4 weeks (range: 1-9 weeks) after exposure. All patients who do not remain chronically infected will be HBsAg negative by 15 weeks after symptom onset
Hepatitis B - Testing in Infants
For Infants born to HBsAg positive mothers, post vaccination testing should be performed 1-2 months after completion of 3 or more doses of a hepatitis B vaccine series.
Testing should not be performed before age 9 months in order to avoid detection of anti-HBs from hepatitis B immune globulin (HBIG) administered uring infnacy and to avoid detection of HBsAg from vaccine - HBsAg can be transiently positive for 1-18 days after vaccination
Hepatitis B - Incubation Period
If symptoms occur, they begin an average of 90 days (range: 60 - 150 days) after exposure to HBV.
How long can HBV live outside the body?
At least 7 days
What percentage of infants will remain chronically infected with HBV?
90%
What percentage of children aged 1 - 5 years will remain chronically infected with HBV?
25-50%
What percentage of adults recover from HBV infection and do not become chronically infected?
95%
Chlamydial Infection / Gonorrhea
Symptomatic cases interview period
60 days prior to onset of symptoms through the date of treatment
Chlamydial Infection / Gonorrhea
Asymptomatic cases interview period
60 days prior to treatment through the date of treatment
Pelvic Inflammatory Disease
Interview period
60 days prior to onset of symptoms through date of treatment
Primary Syphilis
Interview period
Three months (90 days) prior to the onset of symptoms up to the date of adequate treatment
Secondary Syphilis
Interview period
6 1/2 months prior to the onset of symptoms up to the date of adequate treatment.
This is derived by adding the maximum 90 day incubation period, the maximum 5 week duration of a primary lesion, and the maximum ten week latency between primary and secondary syphilis
Early Latent Syphilis
Interview Period
From the date of adequate treatment back 12 months
HIV / AIDS
Interview Period
If there is no test history:
1 year prior to the date that the positive specimen was collected through the date of the interview.
If there is a test history:
6 months prior to a negative test date [through the date of interview]
If there is a spouse:
Ten-year interview period for current or any previous spouses.
- Ryan White Reauthorization Act requires Health Departments receiving Ryan White funds show “good faith” efforts to notify marriage partners of infected patients within the last ten years (unless there is medical evidence, a non-reactive test that this would be unnecessary)
Exception to interview period guidelines
The interview period may be shortened if the original patient received adequate treatment for their infection during the calculated interview period time frame.
The receipt of adequate incidental treatment (within the standard interview period), which is adequate to treat uncomplicated infections, should mark the maximum interview period.
In other words, the date that the adequate treatment was received marks the beginning of the interview period.
