What is the difference between the CDC and the WHO as it pertains to the USA?

Question

With regards to President Trump's defunding of the WHO, here's my question to get a bit more context: With respect to the stated objectives with regards to US national interests, what is the difference between the CDC (Center for Disease Control) and the WHO? Could the CDC conceivably within their mandate take over all the US concerns that the WHO was previously involved in?

(Yes, I am aware that the WHO works internationally (such as it "works" at all), and (I believe) the CDC is a US-based organization focused on the US and the US's interests. I am not concerned with the WHO's actions which do not overlap with the CDC's geopolitical scope of influence, only with the concerns which do not overlap with the CDC's mission statement scope)

Answer 1

So, to answer your first question, the CDC is not just an organization that works in the U.S: The CDC is actually a U.S. Government organization. The WHO, on the other hand, is not.

As to your second question, the WHO seems more dependent on the U.S. and the CDC rather than the other way around (emphasis mine):

CDC is a key partner of the Global Outbreak and Response Network (GOARN), which enables WHO to respond to acute public health events through the deployment of staff and resources. CDC has deployed 674 times into 53 operations and continues to provide support to DRC and surrounding countries amid the ongoing threat of Ebola.

As a founding member of GOARN, the CDC is part of its steering committee and leads on various aspects of the GOARN 2.0 strategy. Other US-based GOARN partners include ProMED, Harvard Humanitarian Initiative, Resolve to Save Lives, Global Virus Network, MWater, Chan Zuckerberg Biohub, Johns Hopkins University, UNICEF, WHO Regional Office for the Americas, US Army Medical Research Institute of Infectious Diseases, and TEPHINET.

US funding has stopped the spread of disease and helped people stay healthy in thousands of humanitarian crisis and disease outbreaks...

Of course, don't take this to mean that the WHO's relationship with the CDC and the US is entirely one-sided. The CDC does appear to get help from WHO (again, emphasis mine):

In close partnership with WHO, the US Centers for Disease Control and Prevention (CDC) facilitates regional training events on foundational principles and concepts in public health emergency management. In 2018, a total of 79 participants representing 23 countries attended regional training events in the WHO AFRO region.

And, according to the CDC, the WHO does help with influenza monitoring:

The World Health Organization’s Global Influenza Surveillance and Response System (GISRS)external icon was established in 1952 to monitor the frequent changes in influenza viruses with the aim of reducing influenza disease impact through the use of vaccines containing currently circulating strains.

Though, reading further, it's unclear who helps who more: the CDC or the WHO (try saying that out loud 5 times fast).

Anyway, the point is, I see no reason why the CDC couldn't pick up the slack if WHO suddenly wasn't involved, though keep in mind that the CDC and the WHO still seem to have a strong relationship in spite of President Trump's actions to cut funding:

“CDC and WHO has had a long history of working together in multiple outbreaks throughout the world, as we continue to do in this one,” CDC Director Robert Redfield said Wednesday on “Good Morning America.” “And so, we’ve had a very productive public health relationship. We continue to have that.”

So that may never happen anyway.

Answer 2

The value of international organizations is that they are a forum for international coordination and are designed to act as a neutral party between countries (even if that often makes them look toothless or too gentle in dealing with bad actors). The WHO doesn't “do” much more than this. In fact, for the whole world, the WHO has fewer staff than the US CDC. That's also why it depends a lot on member states resources for its operational capabilities.

The WHO does have a science division and some health emergency response programs but, unlike the US CDC, it does not run labs or employ researchers. Instead, what it might do is incite countries to focus on some areas, develop standards and procedures, maintain some databases, etc. For example, as part of its health emergency response programs, it maintains a roster of experts who can be called upon to help. These experts are not on the WHO staff (many might actually be on the US CDC staff or in US universities) and the WHO doesn't have the authority to send them anywhere.

It's also instructive to look at the February fact-finding mission on Covid-19 (the mission that resulted in a clear warning about human-to-human transmission, which the WHO has been heavily criticized for not giving earlier). You will notice that it is organized as a WHO-China “joint mission” and that exactly half the members come from the PRC (and traveled separately from the rest of the delegation). From the international members of the team, only two came from the WHO, the rest from different national institutions, including one US scientist (from the NAIAD, not CDC). The WHO is just a vehicle to make things like this happen and this cumbersome structure is necessary to get on-the-ground access in a country like China.

So where does that leave the US? Could the US CDC have the same level of access to other countries' authorities, including countries that are suspicious of the US? Would it be as credible and effective in giving advice and spreading information without going through the WHO? Would a US scientist be on the next joint fact-finding mission with a rival government like China?

Perhaps (in fact, the US CDC used to have a direct collaboration with the Chinese CDC and staff there) but being a US government organization and perceived as such would actually make all that more difficult. Yet, that's valuable even from a narrow US-centered perspective. Pandemics spread very rapidly across the world and a better response elsewhere protects the US too, you cannot neatly separate a “US scope” from the rest of the WHO activities.