Resources for Care Providers

Q/A: HIV Window Period, Testing, PEP, and Acute Infection

Updated January 2016

Window Period

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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.

HIV Testing

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

October 2016


AIDSinfo: Training for Health Care Providers

AIDS Education Training Center (AETC):

Northeast/Caribbean AETC

Resource Library

Centers for Disease Control and Prevention (CDC):

HIV/AIDS Learning Center

HIV Testing

Public Health Image Library 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):

CEI: HIV, HCV & STD Clinical Education Initiative

Emergency Contraception: What You Need to Know

NYS AIDS Institute Training Center

NYS Opioid Overdose Prevention Program

Office of Alcoholism and Substance Abuse Services

Office of Mental Health

Partner Services: What Health Care Providers Need to Know

Payment Options for Adults and Adolescents for Post Exposure Prophylaxis Following Sexual Assault

Payment Options for Adults and Adolescents For Post Exposure Prophylaxis for all other Non-Occupational Exposures

PrEP and PEP Information & Resources

Provider Reporting & Partner Services

Rape Crisis and Sexual Violence Prevention Program

Sexual Assault Forensic Examiner (SAFE) Program

Sexually Transmitted Diseases

Smokers’ Quitline


US Occupational Safety and Health Administration:

Bloodborne Pathogens & Needlestick Prevention

Enforcement Procedures for Occupational Exposure to Bloodborne Pathogens

US Department of Veterans Affairs:

Dermatological Manifestations of HIV Image Library

HIV/AIDS Image Library

Oral Manifestations of HIV Image Library



AHRQ: National Guideline Clearinghouse

AIDSinfo (DHHS guidelines):

CDC HIV/AIDS Guidelines and Recommendations:

IAS-USA Practice Guidelines:



CDC: NIOSH: Preventing Needlestick Injuries in Health Care Settings

New York City (NYC) Health: Reporting Diseases and Conditions


Communicable Disease Reporting Requirements

Court-Ordered HIV Testing of Defendants

Expedited Partner Therapy: A Guide for Partner Care

HIPAA Information Center

HIV Uninsured Care Programs: Summary

HIV/AIDS Laws & Regulations

HIV/AIDS Testing, Reporting and Confidentiality of HIV-Related Information

NYSDOH: Rules, Regulations & Laws

Office for the Prevention of Domestic Violence

Partner Services: What Health Care Providers Need to Know

Payment Options for PEP Following Non-Occupational Exposures Including Sexual Assault

PrEP and PEP Information & Resources

Provider Reporting & Partner Services

Rape Crisis and Sexual Violence Prevention Program

Sexually Transmitted Diseases


Bloodborne Pathogens & Needlestick Prevention

Enforcement Procedures for Occupational Exposure to Bloodborne Pathogens

US Courts:



National Institutes of Health (NIH):

New York City (NYC) Health: STD and HIV Services, including Clinic Locations and Hours

New York eHealth Collaborative: NYEC

New York State (NYS):

Council of Health-System Pharmacists (NYSCHP)

Department of Health

Expanded HIV Testing website

Office of Victim Services

AIDS Drug Assistance Program (ADAP) Formulary

AIDS Institute

Directory of ESAP Providers in New York State

Expanded Syringe Access Program (ESAP): Overview of Law and Regulations

HIV Testing

NYC: Life Net

NYC: Contact Notification Assistance Program (CNAP)

NYC: Expedited Partner Therapy

Medicaid Managed Care and Family Health Plus Pharmacy Benefit Information Center

NYC: Mayor’s Office for People with Disabilities

NYC: Mayor’s Office for People with Disabilities: American Sign Language Interpreters in New York

NYC Quits

NYS PrEP/PEP Provider Voluntary Director

NYS Expanded Syringe Access Program (ESAP)

NYS Safe Sharps Collection Program

NYSDOH HIV Uninsured Care Programs

Office of Alcoholism and Substance Abuse Services

Office of Mental Health

Rapid Testing for HIV

Sexual Assault Forensic Examiner (SAFE) Program

Smokers’ Quitline

STD Clinics in New York State

Wadsworth Center

UCSF Clinician Consultation Center

HIV/AIDS Management

Submit for a case consultation

Phone consultation: 800-933-3413 (M-F, 9am-8pm EST)

US Occupational Safety and Health Administration:

Bloodborne Pathogens & Needlestick Prevention

Enforcement Procedures for Occupational Exposure to Bloodborne Pathogens



AIDSinfo: Drug Database

Antiretroviral Pregnancy Registry: For Health Care Providers

HIV Clinical Resource: 

HIV in Older Adults: Quick Reference Guide

Insomnia Screening & Treatment Quick Reference Guide

Mental Health Screening: Quick Reference Guide

Provider Guide to HIV Testing Quick Reference Card

Substance Use Screening: Quick ReferenceGuide

NYSDOH: CEI: HIV, HCV & STD Clinical Education Initiative

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.



June 2016 Policy Statement: Defining Program Eligibility by HIV Status



All FDA-Approved HIV Medications

March 22, 2018

Listed below are all FDA-approved HIV medications as of March 22, 2018, 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
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs): characteristics
Protease Inhibitors (PIs): characteristics
Fusion Inhibitor: characteristics
Entry Inhibitor: characteristics
Integrase Inhibitors (INSTIs): characteristics
Post-Attachment Inhibitor:
Pharmacokinetic Enhancer:
Combination HIV Medications:

Acronym Key

Full Name
AI AIDS Institute
ALT alanine aminotransferase
ART antiretroviral therapy
ARV antiretroviral
AST aspartate aminotransferase
AUC area under the curve
BID twice daily
BMD bone mineral density
cap capsule 
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
CPK  creatine phosphokinase
CrCl  creatinine clearance
CVD cardiovascular disease
CYP  cytochrome P
DAAs direct-acting antivirals
ECG electrocardiogram
eGFR estimated glomerular filtration rate
EI  entry inhibitor
FDA Food and Drug Administration
FDC fixed-dose combination
GI gastrointestinal
HAV hepatitis A virus
HBsAb hepatitis B surface antibody
HBsAg hepatits B surface antigen
HBV hepatitis B virus
HCV hepatitis C virus
HDL high-density lipoprotein
HLA human leukocyte antigen
HMG-CoA hydroxy-methylglutaryl-coenzyme A
HPV human papillomavirus
HSR hypersensitivity reaction
IDU injection drug use
INR international normalized ratio
INSTI  integrase strand transfer inhibitor
IRIS immune reconstitution inflammatory syndrome
LDL  low-density lipoprotein
MAC Mycobacterium avium complex
Mg magnesium
MI myocardial infarction
MTCT mother-to-child-transmission
MSM men who have sex with men
N/A Not Applicable
NNRTI  non-nucleoside reverse transcriptase inhibitor
NRTI nucleoside reverse transcriptase inhibitor
NYS New York State
NYSDOH New York State Department of Health
OI opportunistic infections
PCP Pneumocystis jiroveci pneumonia
PDE5 phosphodiesterase type 5

post-exposure prophylaxis
nPEP: PEP for non-occupational HIV exposure
oPEP: PEP for occupational HIV exposure
sPEP: PEP for victims of sexual Assault

PI protease inhibitor
PPI proton pump inhibitor
PK pharmacokinetic
PO orally
PPI  Proton pump inhibitor
PrEP pre-exposure prophylaxis
q(n)d every (n) days
q(n)h every (n) hours
QTc QT corrected for heart rate
SCr serum creatinine
SJS Stevens-Johnson syndrome
SSRI selective serotonin reuptake inhibitor
STI sexually transmitted disease
STR single-tablet regimen
TB tuberculosis
TG triglyceride
TID three times a day
WHO World Health Organization

ARV Drug Name Abbreviation Key

Abbreviation Full Drug Name
3TC lamivudine
ABC abacavir
APV amprenavir
ATV atazanavir
ATV/c atazanavir/cobicistat
ATV/r atazanavir/ritonavir
BIC bictegravir
COBI or c cobicistat
DCV daclatasvir
ddC zalcitabine
DLV delavirdine 
DRV darunavir
DRV/c   darunavir/cobicistat
DRV/r darunavir/ritonavir 
DTG dolutegravir 
EFV efavirenz
EFV/TDF/FTC efavirenz/tenofovir disoproxil fumarate/emtricitabine
ETR etravirine
EVG/c elvitegravir/cobicistat
EVG/c/TAF/FTC elvitegravir/cobicistat/tenofovir alafenamide/emtricitabine
EVG/c/TDF/FTC elvitegravir/cobicistat/tenofovir disoproxil fumarate/emtricitabine
EVG/r   elvitegravir/ritonavir
FPV fosamprenavir
FPV/r fosamprenavir/ritonavir
FTC emtricitabine 
IBA ibalizumab
LPV lopinavir
LPV/r lopinavir/ritonavir
MVC maraviroc
NVP nevirapine 
PI/c cobicistat-boosted protease inhibitor
PI/r ritonavir-boosted protease inhibitor 
RAL raltegravir
RPV rilpivirine
RTV ritonavir 
SQV saquinavir
SQV/r saquinavir/ritonavir
T-20 enfuvirtide
TAF tenofovir alafenamide
TDF tenofovir disoproxil fumarate
TPV tipranavir 
TPV/r tipranavir/ritonavir
ZDV zidovudine