Herpes Vaccine ‘Prime & Pull’ Approaches Are Popular

Genital herpes HSV2 therapeutic vaccine candidates remain in studies

tug of war battle

A new research study published by a team from the University of Cincinnati Children’s Hospital Medical Center and Yale University reported the ‘prime and pull’ method may produce a useful therapeutic herpes vaccine.

“Prime and pull” vaccination strategies involve an initial vaccination followed by the local application of a stimulant such as chemokines to recruit immune cells to infected target areas, such as the mucosa.

This animal study was published on August 1, 2019, in the Natures Vaccine online journal, evaluated subunit vaccines (prime) and imiquimod (pull) in the guinea pig model of recurrent Herpes simplex virus type-2 (HSV-2).

Although both the vaccines alone and imiquimod alone reduced recurrent HSV disease, these researchers conclude that the strategy of Prime and topical Pull (intravaginal/topical imiquimod) decreased recurrent HSV more effectively than vaccine alone.

When using glycoprotein vaccines to boost HSV immunity and intravaginal/topical imiquimod to pull immune cells into the vaginal tract, it significantly reduced recurrent genital HSV lesions and the shedding of HSV-2 into the vaginal tract.

This study concluded saying ‘Although this study demonstrates the proof of concept for a therapeutic vaccine, it falls somewhat short when compared to newer antiviral therapies, which can reduce recurrent disease and shedding by almost 90 percent.’

‘Nevertheless, the advantages of vaccine strategies, requiring infrequent administration less than yearly vs. drugs that must be given daily suggest that improving vaccine effectiveness is a worthwhile endeavor.’

Herpes vaccine news

This new study’s finding supports the conclusion from a study published on June 12, 2019, by Yale researcher investigator Akiko Iwasaki, Ph.D., and her colleagues.

These Yale researchers found that the HSV-2 antibody which the body produces in response to vaccination was not present in the vaginal cavity, which is where it is most needed to protect against infection. 

They also learned that when specialized immune cells, called memory B cells, are physically drawn to the genital area, they produce and insert the antibody in the inner vaginal tissue. 

‘Having the antibody circulating in the blood alone is not enough to protect against genital herpes infection, and a different strategy is needed to deliver the protective antibody in the future,’ Dr. Iwasaki said, in a related commentary.

This Yale study’s results may explain why herpes vaccines that have been developed to date have not worked. The findings also support a different approach to vaccination, such as “prime and pull,” which Iwasaki’s lab has been investigating.

Genital herpes symptoms and treatments

Genital herpes is common in the United States, found in about one out of every six people aged 14 to 49 years, says the Centers for Disease Control and Prevention (CDC).  

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Herpes is a common sexually transmitted disease that any sexually active person can acquire. Herpes is similar to syphilis and gonorrhea, which do not have preventive vaccines available either.

Genital herpes is caused by two types of herpesviruses called herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2).

And, about 85 percent of genital herpes cases are undiagnosed and unrecognized, although the carrier could be infectious to their partners, says the CDC.

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Since there is no cure for herpes, antiviral medications can, however, prevent or shorten outbreaks during the period of time the person takes the medication.

Medications make it less likely that you will spread herpes to a sex partner. 

There are 3 major medications in pill form commonly used to treat genital herpes symptoms: acyclovir (Zovirax);  famciclovir (Famvir); valacyclovir (Valtrex).

These medications can shorten a herpes outbreak by a day or two, provided you take them within 24 hours of the first signs of an outbreak. Taken daily, these drugs can also reduce the number of recurrences and decrease viral shedding.

According to research published on April 8th, 2019, women who frequently used a preventive vaginal gel Tenofovir significantly reduced their risk of acquiring genital herpes.

Tenofovir, a nucleotide reverse transcriptase inhibitor, is approved in its oral formulation for the treatment of human immunodeficiency virus infection and Hepatitis B. 

These medications are available at most pharmacies, and co-pay coupons can easily be found at Discounts. 

The CDC says if you have additional questions about how herpes is spread, treated, and prevented, discuss your concerns with a healthcare provider.