For the October issue of Scientific American, I penned a piece on what we can learn from the parallels that exist between the coronavirus and HIV crises.* To this essay, called “Lessons from AIDS for the Covid-19 Pandemic,” I would add one more thought.

A critical difference between AIDS and Covid-19 is that Covid-19 can be controlled by public health means. That continues to be much more difficult for HIV/AIDS.

It is case identification, contact tracing and quarantine that has put the Covid-19 genie back in the bottle in China and several other East Asian countries. Except for sporadic outbreaks, quickly contained, China today is free from Covid-19 — back to work and back to school.

It has never been possible to contain HIV/AIDS in any country at this remarkable level of effectiveness despite more than 35 years of strenuous public health measures and intense biomedical research.

Strategies are different for containing Covid-19 and AIDS because their means of transmission and patterns of infection are different. HIV/AIDS primarily is transmitted sexually, secondarily by needle sharing. Public health approaches to modifying sexual practices, such as limiting the number of partners or promoting condom use, can be partially effective over time but have never been sufficient to tame the AIDS pandemic. Moreover, HIV infection is for life. Those infected are potentially contagious to others for a decade or more.

Covid-19 on the other hand is airborne. Wearing masks, social distancing and short term isolation are sufficient to prevent infection. The SARS-CoV-2 virus quickly peaks within a few days of infection, then rapidly fades. Most people are contagious to others for no more than a week to ten days. These public health measures prevent transmission: testing to identify those infected, contact tracing to identify those exposed, then stringent isolation of those infected for a short period.

Countries can and have controlled Covid-19 in the absence of a vaccine or effective drugs using public health measures alone, something not yet accomplished for HIV/AIDS. Would that this lesson be taken to heart by the regions of the world in which Covid-19 still roams almost freely. Many of those countries have been burdened by faulty governance in combating the pandemic, not by failures of public health techniques.

I believe my proposal in a recent CNN op-ed, Covid-19 Control American Style, to use new technologies and public health measures in the absence of effective drugs and vaccines can bring the pandemic under control in a few short months.

*The essay will be available to non-subscribers on the Scientific American website for a limited time.