Mexico has chosen an ambitious strategy for the containment of COVID-19. After seeking to delay the closing down of economic activity and social contact for as long as possible, it is now preparing for the surge of cases that is to be expected, once community transmission has taken hold. The approach has been criticized as too much of a gamble. It has also been dismissed as a horrendous mistake from a president, Andres Manuel Lopez Obrador, who seems less keen on following advise from science than following his gut feelings, continuing to give hugs, kiss babies and attend rallies. However, the logic of Mexico’s approach is grounded on the experience the country and its public health officials gained from the H1N1 epidemic in 2009, and the notion that the public health system is highly professionalized and capable enough to respond to this crisis in a timely manner. A critical assumption in the Mexican strategy is that local officials and bureaucracies in the health sector are doing their job, actually conveying the relevant epidemiological information to the federal government, in a timely and truthful manner.
If the strategy succeeds, Mexico will become an example of a well crafted public policy that serves the majority of its people, by balancing economic costs with public health imperatives. Mexico delayed many radical actions that were being taken by other countries throughout Latin America early on (Colombia, El Salvador or Argentina, but now almost everywhere in the region), based on the argument that the economic costs of containment would disproportionately fall on poor workers in the informal economy, and that the country had not yet witnessed cases of community transmission. If the government is wrong in its assessment — namely, that the overwhelming majority of cases until March 23 could be traced to contagion from abroad — Mexico may well become the next Italy or Spain. Such alternative scenario of disastrous consequences would be of the government’s own making, due to a failure to take timely actions, that may have contained a pandemic if they had been adopted sooner. The verdict is still out, but it is important to understand at this stage how the Mexican strategy was crafted, and what assumptions of State capacity underly it.
There is little question that Mexico was at the forefront of international response and preparedness for the epidemic. As early as January 10 the Health Secretariat had already noted an outbreak of “a pneumonia with an unidentified causal agent still unconfirmed transmission mechanism” in Wuhan, China. Nine days later Mexico’s Institute for Epidemiology Diagnostics (InDRE) reported having tests available, and a few days later a technical report was already being issued, and a web portal for the epidemic was launched with information and recommendations. The Pan-American Health Organization (PAHO) praised Mexico for being the first country to react and activate its emergency system and having already diagnostic tools in place. Health workers were promptly given recommendations and guidelines for epidemiological surveillance, including formats for following up contacts of potential exposure and reporting.
The first reported cases appeared at the end of February, and a few weeks later the first death occurred. But the government insisted throughout March that the country was still only experiencing phase I infections, clearly traced to foreign travel and close contacts with those travelers, not community transmission. By March 23 the government has started its social distancing strategy, closing down schools and non-essential economic activities, reducing social gatherings and other familiar measures for mitigation (i.e. flattening the curve policies). Most of the rest of Latin America took these measures much earlier. The Mexican strategy makes sense only if the federal government is correct in believing that the cases circulating in the country thus far were not the product of community transmission. The main reason why Italy or Spain have been hit so hard by the epidemic is because the virus was more widespread than national public health experts expected.
Very small differences in the underlying prevalence of the virus, given the exponential growth of the contagion, can make a big difference in the stress on the medical system. And a few days of difference in when to start an intervention of containment and mitigation will determine the evolution of the epidemiological curve. This can be seen quite clearly in simulations using the epidemic calculator provided by Gabriel Goh. The only difference between these curves, is that the first one starts with 82 cases, most of them NOT requiring hospitalization (most of them would hence have mild symptoms and probably remain undetected); while the second one starts from 646 cases. In the simulation the intervention by the government is started in day 25, reducing the reproduction number (Ro) to half of its initial value (in this simulation the relatively conservative 2.1 is used).
The Mexican strategy is grounded on assumptions about the capacity of the State, and in particular the public health system. The epidemiological surveillance system of Mexico is rather sophisticated, drawing from the accumulated experiences of the H1N1 epidemic of 2009, as well as the outbreaks of Zika and Dengue from past years. The deputy Secretary for public health, Hugo Lopez-Gatell, has become the main architect and spokesman of the federal government strategy. He has a proven publication record of academic papers, dealing with issues including influenza, pulmonary disease, community responses, hospital triage, zika and dengue, and disease surveillance systems. He might not be the vice-president of Taiwan, but he has clearly become the Mexican leader in charge of the national strategy and response.
An example of the substantial capacity of the Mexican State, regarding public health surveillance, can be seen in the graph showing influenza tracking. Analogous tracking is done with arboviruses (like Zika and Dengue), and many other diseases. This is not a novel approach, but something that is highly professionalized within the Mexican health system.
Notwithstanding this evident capacity, it is important to note that the health system in Mexico has been under budgetary stress, particularly with the current federal government measures of fiscal austerity. And from the perspective of political economy, one should note that bureaucracies are never perfect agents of their principals. Even though incentives may be designed to improve performance, there are always moral hazard challenges. Agents of the State may be tempted to hide information or not reveal it truthfully, particularly if they believe they can get away with it or that providing true reports may lead to a poor assessment of their performance. On the citizen side there are always problems that may be related to how likely patients are to report their own disease, as well as the truthful revelation of their background, personal networks and movements (which may include lying about travel history and close contacts).
A lot of social science research suggests that these agency challenges are mitigated to the extent that there is widespread trust in public officials and institutions and a high degree of professionalization among bureaucracies. Mexico’s health system has a complex architecture (see the excellent work of Laura Flamand for some insight), with variations in capacity, professionalization and trust. The COVID-19 crisis will be the greatest test the health system has faced so far. The crucial issue is whether the Mexican Public Health System has been able to effectively track all the relevant cases, and identify any anomalous patterns in the epidemiological data.
There are two critical pieces of information that the federal government has been tracking, and gave it the confidence in keeping the course, despite recurrent calls within Mexico and abroad to declare a shutdown, “shelter in place”, or adopt other more stringent policies of containment and mitigation. The first one was that the system of epidemiological surveillance had not shown any obvious anomaly. The graph above shows, for example, the likely influenza cases in the country, that kept up with the usual seasonal patterns. There was no upsurge in pulmonary disease deaths or cases tracked in the hospitals and clinics. In the case of China we know that even before the virus was identified, the government had witnessed an increase in pneumonias (which the authoritarian regime tried to hide). Hence, health surveillance systems suggested no community transmission. That is, assuming the capacity of the Mexican state to make the health conditions of its population legible. Though that legibility may be reduced by administrative failures, underfunding, drug related violence, or other unobserved local factors, there is no obvious event or shock that would suggest a change in health capacity in Mexico over the past months.
A second important element of surveillance came from testing patients that were suspected to have influenza, but had not tested positive to known virus strains. This was a strategy that was first reported by the Health Secretariat on February 27. The number of cases was relatively small, which might mean that the sampling had no statistical power to detect small effects that may have been circulating among a very large population. But the strategy was based on testing cases that clearly had symptoms of a respiratory disease. None of those tests returned a positive result. The limitation of the strategy was precisely its approach based on symptomatic cases. There is no way for that information to reflect that potential asymptomatic cases, that we now know may be driving quite a bit of the transmission of the disease. But coupled with the information from disease patterns that remained relatively normal, it gave the federal government confidence in that community transmission had not started. The cases that had arrived to the health system so far had mostly been tracked to travel and contagion from contacts and relatives that had traveled abroad.
The strategy Mexico followed was hence based on scientific evidence and a sophisticated understanding of epidemiology of disease dynamics. It also incorporated a social component, by having health workers contact all the cases that could be susceptible to transmission. And the Mexican government provided its health workers very early on all the instruments they needed to implement the surveillance. The Mexican government was not capable, however, to put in place a supplemental system like the one practiced by Taiwan, in which border crossing were connected to health and demographic data (in order to ensure that citizens would not lie about their whereabouts and contacts), health workers were trained intensely, and testing was performed for all contacts.
The risk of the strategy has always been that many asymptomatic cases may have been spreading the virus unknowingly, or that there may be many more community transmission cases among patients with precarious access to health, who may not have been detected by the surveillance system. In that scenario, Mexico may have taken its social distancing measures too late.
The Mexican strategy has hence been reasonable, though risky. However, a serious problem throughout has been to explain to the public with greater transparency what the government has done. The communication strategy of the Mexican government has not been effective in generating citizen trust. Federal health officials were truly creative with a character called Susana Distancia (your healthy distance), who encourages social distancing and healthy prevention. But the health officials did not communicate clearly and with transparency the epidemiological data they have been relying on, or why they have been so confident in adopting a relatively unusual strategy. And the President’s behavior did not help, with his recurrent dismissal of the imperative to limit personal contacts.
Such failure in generating citizen trust goes beyond the ideological rifts that already exist in a country polarized by a hugely popular President, but who is intensely criticized and disliked by many. This is a shame, because with better communication and trust, citizens would have been more likely to understand the importance of reporting any unusual sickness early on; and health workers would have realized the imperative of being as truthful as possible in their reports and their vigilance. Instead, there is reasonable doubt, that will remain for the coming days, of whether the Mexican State has been capable of handling one of the greatest challenges of our time.