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Dr. Sheryl Malone-Thomas

PrEP Expert

Chief Nurse and Family Nurse Practitioner (FNP)
Houston Health Department Bureau of HIV/STD and Viral Hepatitis Prevention

Dr. Sheryl Malone-Thomas is the Houston Health Department’s resident expert on Pre-Exposure Prophylaxis (PrEP) and supervises all of HHD’s Houston area clinics. Her role involves persuading clinic visitors who face the highest risk of acquiring HIV to get themselves tested for the virus and to see if they are eligible to get on PrEP.

Dr. Malone-Thomas has 30 years of overall nursing experience, including 18 years of nurse practitioner experience in the areas of leadership, primary care, hepatology and liver transplant, tuberculosis, family planning and HIV/STD and viral hepatitis prevention. She has been with HHD since 2012.

Dr. Malone-Thomas earned her family of nurse practitioner’s degree at Houston Baptist University. She also earned a doctorate of nursing practice degree at Chatham University and a bachelor of science in nursing from Lamar University.

FAQs about PrEP

Truvada, or PrEP (Pre-Exposure Prophylaxis), was approved by the Food and Drug Administration (FDA) in 2012 and has been found to reduce the risk of sexually acquired HIV-1 in adults and also in adolescents who weigh more than 77 pounds.

Truvada is 99% effective, but it is important to note that research studies involving Truvada included condom use as a means of reducing risk of HIV-1. HIV is a blue pill that should be taken every day around the same time. Once you swallow Truvada, it goes to the gut, ends up in your blood stream and stops HIV from entering your blood.

(Shortly after the HIV enters the cell, an enzyme called reverse transcriptase liberates the positive-sense single-stranded RNA genome from the attached viral proteins and copies it into a complementary DNA (cDNA) molecule. Truvada works by tricking reverse transcriptase into thinking it is one of these molecular building-blocks. However, it is just different enough that when used to create DNA, Truvada actually stops the DNA from being made.)

Yes. You must be HIV negative to take Truvada for PrEP.

It takes about 9 days for PrEP to work effectively in men, and 21 days to work effectively in women.

The most common side effects are: headache (7%); abdominal pain (4%); diarrhea, nausea, dizziness, insomnia, abnormal dreams, rash, tiredness and weight loss (3%). It is important to note that diarrhea, nausea, and abdominal discomfort usually resolve within four days of starting Truvada.

The most serious side effects are: New or worse kidney problems, bone problems (i.e., pain, softening or thinning of the bones), too much lactic acid in your blood (symptoms: weakness, muscle pain, short of breath, fast breathing, stomach pain with nausea, and vomiting).

Note: Studies have indicated that only about 6% of patients in one trial (iPrEx Trial), and 0.1% of  patients in another trial (Partners PrEP Trial), stopped Truvada due to adverse events.

HHD clinics check liver and kidney function prior to a patient starting Truvada; one month after starting PrEP; and every three months thereafter — unless it is necessary to check more frequently. HHD also checks for all other STDs, including syphilis, gonorrhea, chlamydia and both Hepatitis B and C.

Yes. You must be HIV negative to take Truvada for PrEP. HHD checks HIV status prior to any patient starting PrEP, 1 month after starting PrEP, and at least every three months thereafter.

Truvada (PrEP) is used in the Pep regimens, but not alone. You must take another antiviral such as Tivicay or ISENTRESS, along with Truvada to prevent HIV, if in fact, you have been exposed to HIV. May I add that Pep has to be started within three days in order to decrease your chances of contracting HIV.

Condomless sex, anonymous sex partners, multiple sex partners, health care disparities and a lack of knowledge are all factors in the HIV risk trending higher among these groups.

HIV infections increased by 10 percent among those 20-29 years old between 2011 and 2016

 Lifetime Risk of HIV based on Ethnicity  




Overall 1 in 68       1 in 253
African American 1 in 22        1 in 54


MSM Lifetime risk of HIV diagnosis:

African American: 1 in 2

Hispanic: 1 in 4

Caucasian: 1 in 11

  • Among MSM, African Americans and Hispanics are at the highest risk for HIV infection
  • Receptive partners of anal sex are 13 times more likely to become infected with HIV than insertive partners
  • MSM are 83 times more likely to become infected with HIV than heterosexual men


Hispanic 1 in 51    1 in 256
Native Hawaiian/
Pacific Islander
1 in 95    1 in 432
Caucasian 1 in 140    1 in 941
Asian 1 in 176    1 in 943
  • Among transgender women, HIV prevalence is 34 times greater than cisgender adults.. Additionally, 72 percent of transgender women perceive themselves to be at low or no HIV risk.
  • An estimated 69 percent of transgender men report condomless sex with cisgender men
  • 89 percent of transgender people believe that it is important for their HCP to know their gender identity

Low perception of risk, condomless sex, a large population of incarcerated black males, health care disparities and multiple sex partners are all factors.

Call anyone of our health centers to schedule an appointment, or call our main number in the HIV/STD, and Viral Hepatitis Bureau at 832-395-5010 and inquire about PrEP. Each clinic sees walk-in patients if time permits.

Kidney failure; uncontrolled type 2 diabetes; uncontrolled high blood pressure; osteoporosis. Also, patients taking high doses of non-steroidal anti-inflammatory medications such as Advil, Ibuprofen, or Motrin are also at a risk for causing problems with the kidneys.

PrEP does not protect against other STDs.

The best practice is to use condoms to protect against all STDs.

It depends on how many hours you are late taking the pill. For example, if you are 12 hours late, do not try to play catch-up. Start taking the pill at the regularly scheduled time the next day. If you are only one to two hours late, take the pill as soon as possible and go back to the regular time you take the pill the next day.

Yes. PrEP can be taken at the same time with birth control.

It is unsafe, and contraindicated to take medications prescribed for another person.

Gilead, the pharmaceutical company who makes Truvada, has assistance for both insured and uninsured patients.

Sharpstown Community Health Center
Mondays and Tuesdays PrEP Clinic

Sunnyside Community Health Center
Wednesday morning PrEP Clinic

Northside Community Health Center
Thursdays PrEP Clinic.

Treatment as prevention is a concept in public health that the transmission of an infection can be prevented by treating people with the infection so that they become less likely to transmit the infection to others. In other words, if your sex partner is living with HIV, and he or she takes their medication as prescribed and becomes virally supressed (undetectable), they are less like to transmit the HIV infection to you.

Health Programs

PrEP is approved for daily use and is taken in pill form.  It significantly reduces the risk of HIV infection in people who are HIV negative. 
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Getting and keeping your HIV under control is the best thing people living with HIV can do to stay healthy.
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HHD Centers
Assistance for anyone getting tested for HIV and getting started on PrEP after getting tested for eligibility.
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PrEP Providers
Houston area HIV care providers
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HIV Providers
Houston area HIV care providers
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