**1. Introduction**

Currently, the UNAIDS estimates that there are 38.4 million people with human immunodeficiency virus (HIV)-1 infections worldwide as of 2021. Of these 38.4 million people, approximately a quarter of people (25.2% or 9.7 million) with HIV-1 infections are not accessing the standard of care, antiretroviral therapy (ART) [1].

ART is the only known treatment to slow the progression to acquire immunodeficiency syndrome (AIDS) and to prevent the spread of infection, but there are several shortcomings with this therapy, as discussed in further detail in the next section.

HIV-1 infection and its progression to AIDS is a global health crisis and disproportionally affects low-income countries, particularly those in Sub-Saharan Africa. Though there is 12% of the global population in Sub-Saharan Africa, this region has 71% of the world's population of people with HIV infections [2]. HIV infection is the highest in young men and women in child-bearing age [3], with women having up to eightfold higher risk for acquiring HIV than their male cohorts [2]. These women with ages between 15 and 24 are also more likely to acquire the infection five to seven years before men in the same age group [2]. Given the great number of women impacted by HIV-1 infections, this leads to

pediatric infections from perinatal transmission or transmissions from breast milk. Notably, pediatric infections are very different than adult infections and detailed in Section 5.

It is widely accepted that immunization is the most cost-effective, scalable, and lasting public health intervention method to end the HIV epidemic [4]. Though a prophylactic HIV-1 vaccine has been researched and developed for several decades, there is yet to be a licensed vaccine on the market. The main obstacles preventing the generation of a successful vaccine are as follows: (i) HIV-1 has a high rate of mutation and viral replication, with extraordinary worldwide genetic diversity [4], as discussed in the following paragraph and "immune response" section, (ii) immune response behind an HIV-1 infection is never completely eradicated, leading to an incomplete understanding of correlates of immune protection [4], (iii) HIV-1 creates a latent reservoir unlike other viral infections, as reviewed in Section 3, (iv) there is no appropriate animal model [4], and (v) there are funding issues associated with vaccine development [4, 5].
