Q/A: HIV Window Period, Testing, PEP, and Acute Infection
Updated January 2016
What is the “window period”? The “window period” occurs between the time of HIV infection and the time when diagnostic tests can detect HIV. The length of the window period varies depending on the type of diagnostic test used and the method the test employs to detect the virus.
Can an infected person transmit HIV to others during the window period? Yes. During the window period, and despite a negative test result, an HIV-infected person may transmit the virus to others.
How long can the window period last? The window period varies slightly from person to person, but virtually everyone infected with HIV develops antibodies within 3 months of infection.
When is follow-up HIV testing warranted? If a person tests negative for antibodies 3 months after a potential exposure to HIV, he or she does not require further testing. However, follow-up testing is warranted for individuals with repeated potential exposures during that 3-month period or when the antibody test results are incompatible with the person’s clinical history.
What are the recommendations for routine HIV testing for adults? The New York State Department of Health (NYSDOH), the US Centers for Disease Control and Prevention (CDC), and the US Preventive Services Task Force (USPSTF) recommend offering HIV testing to all adults as part of routine healthcare. New York State law requires that all persons between the ages of 13 and 64 be offered an HIV test at least once. The law also requires healthcare providers to offer an HIV test to any person, regardless of age, if there is evidence of risk activity.
Who should be offered ongoing HIV testing? Testing should be offered at least annually to anyone whose behavior increases his or her risk for exposure to HIV. Since many people choose not to disclose their risk behaviors, providers should consider adopting a low threshold for recommending the test.
How often should individuals who engage in high-risk behavior be tested? Clinicians should recommend testing every 3 months for individuals who engage in unprotected anal sex, sex with multiple or anonymous partners, needle-sharing, or sex with partners who share needles. In these high-risk cases, testing is used to ensure early access to care and to prevent transmission to others if the patient becomes infected.
Should pre-exposure prophylaxis (PrEP) be offered to individuals with high-risk behavior? Yes. PrEP to prevent HIV infection should be considered for persons with ongoing high-risk behaviors. PrEP should be prescribed as part of a comprehensive prevention strategy that includes risk-reduction counseling about safer sex practices, condom use, and safer injection practices, as well as referral to syringe exchange programs and drug treatment services when appropriate. The NYSDOH AIDS Institute guidance for PrEP is available online.
|NYSDOH, CDC, and USPSTF recommend HIV testing for all adults as a routine part of healthcare.|
HIV Diagnostic Testing Algorithm
What is the HIV diagnostic testing algorithm? This is a laboratory-based diagnostic algorithm that recommends a combination of laboratory tests performed in a defined sequence. Extensive evidence supports this algorithm for maximal sensitivity, specificity, and accuracy for HIV detection.
What is the initial test of the HIV diagnostic testing algorithm? The algorithm begins with an immunoassay (sometimes called a “4th generation test”) that detects both HIV-1 and HIV-2 antibodies and HIV-1 p24 antigen. The HIV-1 p24 antigen appears before antibodies develop so that acute HIV infection can sometimes be detected.
What steps are taken when the initial test is reactive? Specimens reactive on the initial assay are tested with a supplemental assay that differentiates HIV-1 and HIV-2 antibodies. Specimens that are reactive on the initial assay but nonreactive or indeterminate on the antibody differentiation assay are then tested for HIV-1 RNA to differentiate acute HIV infection from a false-positive screening result. The final interpretation is based on a combination of test results. The NYSDOH Testing Toolkit provides more information about HIV diagnostic tests and the algorithm. The NYSDOH AIDS Institute’s guidelines on HIV testing and monitoring patients on ART should be consulted as well.
|It is important to know which HIV tests are being used by your agency or laboratory so you can provide patients with accurate information regarding their HIV test results.|
Exposure to HIV and Post-Exposure Prophylaxis (PEP)
What are the recommendations for persons who report an exposure? HIV exposure is a medical emergency. If the patient reports a significant exposure, the first dose of PEP should be given. Other testing and evaluation can be continued following the first dose. When PEP is initiated immediately after an exposure (ideally, within 2 hours), it can prevent HIV infection. Please consult the NYSDOH AIDS Institute’s clinical guidelines on PEP for prevention of HIV infection.
PEP is most likely to prevent infection when initiated within 36 hours of exposure. The decision to start PEP later, beyond 36 hours post-exposure, should be made jointly by the clinician and the exposed individual, with the understanding that PEP is less likely to prevent HIV infection the longer it is delayed.
Can HIV infection be detected immediately after exposure? HIV infection is not immediately detectable.
How often should an exposed individual be tested? NYSDOH protocols recommend testing at baseline and at 4 and 12 weeks post-exposure.
Are the guidelines for PEP different for different types of exposure? The NYSDOH AIDS Institute provides specific guidelines for PEP following occupational exposure, non-occupational exposure, and sexual assault.
Acute HIV Infection
What is acute HIV infection? Acute HIV infection is the very early, initial stage of HIV infection when the virus is multiplying rapidly and the body has not yet developed antibodies to fight it.
What are the symptoms of acute HIV infection? Symptoms of acute HIV infection are similar to flu symptoms and may include fever, fatigue or malaise, joint pain, headache, loss of appetite, rash, night sweats, myalgia, nausea or diarrhea, and pharyngitis.
If acute HIV infection is suspected, what steps should be taken for testing? If a patient presents with signs/symptoms of acute HIV, then HIV RNA testing should be requested in conjunction with an initial 4th generation (recommended) or 3rd generation (alternative) screening test. In the absence of serologic evidence of HIV infection:
- If HIV RNA is not detected, no further testing is needed.
- Detection of HIV RNA with ≥5,000 copies/mL indicates a preliminary diagnosis of HIV infection.
- Detection of HIV RNA with <5,000 copies/mL requires repeat HIV RNA testing.
- If a diagnosis of HIV infection is made on the basis of HIV RNA testing alone, a new specimen should be collected 3 weeks later, and HIV diagnostic testing should be repeated.
|When acute infection is suspected, an HIV RNA assay should always be requested in conjunction with an HIV screening test.|
Why is it so important to diagnose HIV infection during the acute phase? In most infected persons, HIV viral load increases quickly after exposure, peaks at about 3 weeks post exposure, and then declines over the next several months. An HIV-infected person is most infectious during this acute phase because of the high viral load. The NYSDOH AIDS Institute clinical guideline on Diagnosis and Management of Acute HIV Infection recommends ART for all patients diagnosed with HIV infection.
Is specialty consultation required for pregnant women with acute HIV infection? Yes. If acute HIV infection is suspected in a pregnant woman, request HIV RNA testing in addition to a 4th generation (recommended) or 3rd generation (alternative) screening test. If reactive, consultation with a provider experienced in diagnosing and evaluating acute HIV infection is important. Earlier diagnosis and treatment can reduce the risk of mother-to-child transmission. For more information, see Acute HIV Infection in Pregnancy.
How can I locate an experienced HIV care provider? The CEI line, which is available through the NYSDOH Clinical Education Initiative, provides access to providers with experience in acute HIV infection: 866-637-2342.
Online Resources for Education, Information and Services
AIDSinfo: Training for Health Care Providers
AIDS Education Training Center (AETC):
Centers for Disease Control and Prevention (CDC):
E-patients.net: Salzburg Statement on Shared Decision Making
National Center for Transgender Equality: 2015 U.S. Transgender Survey
New York City DOHMH: Making the Sexual History a Routine Part of Primary Care
New York State Department of Health (NYSDOH):
UCSF: HIV InSite
US Occupational Safety and Health Administration:
US Department of Veterans Affairs:
AIDSinfo (DHHS guidelines): https://aidsinfo.nih.gov/
CDC HIV/AIDS Guidelines and Recommendations: http://www.cdc.gov/hiv/guidelines/
IAS-USA Practice Guidelines: https://www.iasusa.org/guidelines
New York City (NYC) Health: Reporting Diseases and Conditions
US Courts: courtsystem.org
National Institutes of Health (NIH): Clinicaltrials.gov
New York City (NYC) Health: STD and HIV Services, including Clinic Locations and Hours
New York eHealth Collaborative: NYEC
New York State (NYS):
UCSF Clinician Consultation Center
Phone consultation: 800-933-3413 (M-F, 9am-8pm EST)
US Occupational Safety and Health Administration:
AIDSinfo: Drug Database
Antiretroviral Pregnancy Registry: For Health Care Providers
HIV Clinical Resource:
University of Liverpool: HIV Drug Interactions
UCSF HIV InSite: Database of Antiretroviral Drug Interactions
HIV Care Provider Definitions
New York State Department of Health AIDS Institute, April 2017
Experienced HIV care provider: Practitioners who have been accorded HIV-Experienced Provider status by the American Academy of HIV Medicine (AAHIVM) or have met the HIV Medicine Association’s (HIVMA) definition of and experienced provider are eligible for designation as an HIV Experienced Provider in New York State.
Nurse practitioners and licensed midwives who provide clinical care to HIV-Infected individuals in collaboration with a physician may be considered HIV Experienced Providers provided that all other practice agreements are met (8 NYCRR 79-5:1; 10 NYCRR 85.36; 8 NYCRR 139-6900)
Physician assistants who provide clinical care to HIV-infected individuals under the supervision of an HIV Specialist physician may also be considered HIV Experienced Providers (10 NYCRR 94.2)
Expert HIV care provider: A provider with extensive experience in the management of complex patients with HIV.
All FDA-Approved HIV Medications
November 10, 2017
Listed below are all FDA-approved HIV medications as of August 17, 2016, with links to the AIDSinfo drug database. For professionals, the links open the FDA label pages, and for consumers, the links open the AIDSinfo patient information pages. The list is organized by drug class, with individual drugs listed in alphabetical order. Combination drugs are also listed in alphabetical order.
Nucleoside Reverse Transcriptase Inhibitors (NRTIs): characteristics
- Abacavir (ABC; Ziagen): FDA label | Patient info
- Didanosine (ddI; Videx; Videx EC [enteric-coated]): FDA label (delayed release capsule) | FDA label powder | Patient info
- Emtricitabine (FTC; Emtriva): FDA label | Patient info
- Lamivudine (3TC; Epivir): FDA label | Patient info
- Stavudine (d4T; Zerit): FDA label | Patient info
- Tenofovir Disoproxil Fumarate (TDF; Viread): FDA label | Patient info
- Zidovudine (AZT, ZDV; Retrovir): FDA label | Patient info
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs): characteristics
- Efavirenz (EFV; Sustiva): FDA label | Patient info
- Etravirine (ETR; Intelence): FDA label | Patient info
- Nevirapine (NVP; Viramune, Viramune XR [extended release]): FDA label | Patient info
- Rilpivirine (RPV; Edurant): FDA label | Patient info
Protease Inhibitors (PIs): characteristics
- Atazanavir (ATV; Reyataz): FDA label | Patient info
- Darunavir (DRV; Prezista): FDA label | Patient info
- Fosamprenavir (FPV; Lexiva): FDA label | Patient info
- Indinavir (IDV; Crixivan): FDA label | Patient info
- Nelfinavir (NFV; Viracept): FDA label | Patient info
- Ritonavir (RTV; Norvir): FDA label | Patient info
- Saquinavir (SQV; Invirase): FDA label | Patient info
- Tipranavir (TPV; Aptivus): FDA label | Patient info
Fusion Inhibitor: characteristics
Entry Inhibitor: characteristics
Integrase Inhibitors (INSTIs): characteristics
- Dolutegravir (DTG; Tivicay): FDA label | Patient info
- Elvitegravir (EVG; Vitekta): FDA label | Patient info
- Raltegravir (RAL; Isentress): FDA label | Patient info
- Abacavir/Lamivudine (ABC/3TC; Epzicom): FDA label | Patient info
- Abacavir/Dolutegravir/Lamivudine (ABC/DTG/3TC; Triumeq): FDA label | Patient info
- Abacavir/Lamivudine/Zidovudine (ABC/3TC/ZDV; Trizivir): FDA label | Patient info
- Atazanavir/Cobicistat (ATV/COBI; Evotaz): FDA label | Patient info
- Darunavir/Cobicistat (DRV/COBI; Prezcobix): FDA label | Patient info
- Efavirenz/Emtricitabine/Tenofovir Disoproxil Fumarate (EFV/FTC/TDF; Atripla): FDA label | Patient info
- Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Alafenamide Fumarate (EVG/COBI/FTC/TAF; Genvoya): FDA label | Patient info
- Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Disoproxil Fumarate (EVG/COBI/FTC/TDF; Stribild): FDA label | Patient info
- Emtricitabine/Rilpivirine/Tenofovir Alafenamide Fumarate (FTC/RPV/TAF; Odefsy): FDA label | Patient info
- Emtricitabine/Rilpivirine/Tenofovir Disoproxil Fumarate (FTC/RPV/TDF; Complera): FDA label | Patient info
- Emtricitabine/Tenofovir Alafenamide (FTC/TAF; Descovy): FDA label | Patient info
- Emtricitabine/Tenofovir Disoproxil Fumarate (FTC/TDF; Truvada): FDA label | Patient info
- Lamivudine/Zidovudine (3TC/ZDV; Combivir): FDA label | Patient info
- Lopinavir/Ritonavir (LPV/r; Kaletra): FDA label | Patient info
|AUC||area under the curve|
|BMD||bone mineral density|
|CCB||calcium channel blockers|
|CD4||CD4 T lymphocyte|
|CEI||NYSDOH Clinical Education Initiative|
|CKD||chronic kidney disease|
|Cmax||maximum plasma concentration|
|Cmin||minimum plasma concentration|
|CNS||central nervous system|
|eGFR||estimated glomerular filtration rate|
|FDA||Food and Drug Administration|
|HAV||hepatitis A virus|
|HBsAb||hepatitis B surface antibody|
|HBsAg||hepatits B surface antigen|
|HBV||hepatitis B virus|
|HCV||hepatitis C virus|
|HLA||human leukocyte antigen|
|IDU||injection drug use|
|INR||international normalized ratio|
|INSTI||integrase strand transfer inhibitor|
|IRIS||immune reconstitution inflammatory syndrome|
|MAC||Mycobacterium avium complex|
|MSM||men who have sex with men|
|NNRTI||non-nucleoside reverse transcriptase inhibitor|
|NRTI||nucleoside reverse transcriptase inhibitor|
|NYS||New York State|
|NYSDOH||New York State Department of Health|
|PCP||Pneumocystis jiroveci pneumonia|
|PDE5||phosphodiesterase type 5|
|PPI||proton pump inhibitor|
|PPI||Proton pump inhibitor|
|q(n)d||every (n) days|
|q(n)h||every (n) hours|
|QTc||QT corrected for heart rate|
|SSRI||selective serotonin reuptake inhibitor|
|STI||sexually transmitted disease|
|TID||three times a day|
|WHO||World Health Organization|
ARV Drug Name Abbreviation Key
|Abbreviation||Full Drug Name|
|COBI or c||cobicistat|
|EFV/TDF/FTC||efavirenz/tenofovir disoproxil fumarate/emtricitabine|
|EVG/c/TDF/FTC||elvitegravir/cobicistat/tenofovir disoproxil fumarate/emtricitabine|
|PI/c||cobicistat-boosted protease inhibitor|
|PI/r||ritonavir-boosted protease inhibitor|
|TDF||tenofovir disoproxil fumarate|