Advocates recognize May 18, 2017 as the 20th anniversary of HIV Vaccine Awareness Day, an important day to mark the need to develop this safe, effective and accessible prevention tool to augment the current biomedical and behavioral prevention options we have now to curb the incidence of new HIV infections in each country. Many ask, “Why is that so when we now have, singly or in strategic combination: oral preexposure prophylaxis, harm reduction, ways to lower a person’s HIV viral load so that undetectable=untransmissible, behavioral programs, voluntary medical male circumcision, condom use, prenatal treatment of mothers during pregnancy and care for infants? These are capable – if only they were perfectly funded and sustainably deployed – of achieving the UNAIDS goal of Zero new infections.”
In the last year for which numbers were generated (2015), 2.1 million people globally became newly infected, a number not much decreased from the previous year, and HIV infections are rising in some populations. In South Africa alone, 2000 girls and young women become infected with HIV every single week of the year. In Canada, new diagnoses (which are not the same as new infections) have remained flat since 2012 without declining although local isolated progress is evident. This despite the availability of an arsenal of tools to prevent people from acquiring HIV.
Bad epidemics take time, will, money, medicine and effort to curb and eradicate. It took almost 200 years to eradicate smallpox worldwide after Edward Jenner first used a cow form of the deadly virus to inoculate people against the fatal disease. Deadly viruses and bacteria can resurface and explode in a population again after quieting down due to other public control efforts. Effective vaccines are an excellent way to lessen that threat when they are provided to everyone who needs them.
Multiple factors hinder our ability to use current prevention methods to stop new HIV infections entirely, including:
Difficulties with personal adherence-based long term prevention strategies (fatigue, lapses, accident, disrupted supply, determinants of health);
Social/legal/economic barriers to fully fund or support commitments or programs for all at risk;
Recidivism/pathogen reintroduction in the absence of complete eradication;
Real world implementation limits such as effective delivery and monitoring by healthcare systems that are under pressure to address multiple diseases;
Non-efficacy of existing prevention against violence or stigma that block personal adoption of prevention methods.
HIV is also a persistent natural threat in an evolutionary sense no matter what we do. HIV entered human populations likely a century ago from a virus found in chimpanzees. Animal to human transmission was not a one-time event and may introduce new HIV forms in the future that we must guard against long term.
"Scientists and advocates have been searching for an HIV vaccine for over 30 years. That seems like a long time, but vaccines for other diseases have taken even longer to discover."
The problems raised by these factors must NOT ever lead us away from the imperative to go forward with all deliberate speed to deploy those prevention tools now in hand and solve the difficulties. But without an effective vaccine against a virus that constantly mutates and connives to evade the fragile and complex strategies we find to stop it, the prospect of ending new infections is precarious.
Two recent studies by leading global experts used the most powerful, robust and data driven techniques available to show what we can expect if no vaccine is found and we rely only on current methods to prevent new infections. In the first study, under the status quo, 49 million new infections would occur by 2035, 27 million if HIV drugs reach the UNAIDS 90-90-90 goals for people with HIV; a partially effective vaccine could avert 17 million more new infections. In the second study, which looked at achieving agreed upon commitments to use our current prevention tools, 550,000 new infections would occur in the year 2070, 53 years from now. A partially effective vaccine deployed in the year 2027 would result in 122,000 new infections in the year 2070, a much better future.
Even with perfect rollout of treatment to reduce disease and virus levels and other prevention options, we need a vaccine. That’s clear. The hesitancy we see in many countries to meet prevention commitments should give us pause about relying only on the tools we have now. Failing to add vaccines - the most successful medical measure to save lives that science has historically provided in response to raging epidemics - would be a serious mistake.
Scientists and advocates have been searching for an HIV vaccine for over 30 years. That seems like a long time, but vaccines for other diseases have taken even longer to discover. It took over 40 years to invent the modern polio vaccine; a search for an effective vaccine against tuberculosis in adults still continues after 100 years. HIV is likely one of the most difficult to beat because of its high diversity, a thick shield on its surface and its shape-shifting abilities. Several approaches to find a vaccine show promise, including ongoing clinical trials and also early research for the “classical” approach of helping a person’s own immune system to generate antibodies that block infection, an approach under development in Toronto and worldwide.
Meanwhile, we must use all the tools at hand to prevent HIV, provide best care for people who have the virus, eliminate stigma and violence and search for a cure to this disease. Canada’s HIV vaccine research and advocacy community recently delivered a strong consensus statement to government authorities describing steps to move this research forward. That too deserves strong support.
About the Author: Robert Reinhard is the Community Liaison, Canadian HIV Cure Enterprise (CanCURE). Robert gratefully acknowledges HIV vaccine researchers, Jean-Phillipe Julien, PhD (Sickkids Hospital) and Bebhinn Treanor, PhD (University of Toronto), for their thoughtful review of this article.