Wednesday, October 20

The third wave of infections grows in Mexico

The third peak of the pandemic has reached Mexico. On July 15, Mexico registered 12,821 infected by the new coronavirus disease, mainly in its new alpha, gamma and delta variants. The weekly average has already clearly exceeded the levels of the first peak, which is now just one year old. Infections have tripled in a week in the country, although the number of hospitalizations and deaths has not grown at the same rate. Certainly, the majority of infections are occurring in younger profiles, less susceptible to severe evolutions of the covid, but also among unvaccinated populations, much more exposed.

Deaths, a harsher and clearer indicator of the severity of the pandemic due to its lower susceptibility to underreporting (an asymptomatic case is easier to miss than a severe one, and cases are better detected now than a year ago), already they have started to rebound. It remains to be seen how much it will accelerate in the coming weeks. The hope of lower growth thanks to vaccination is diminished by the fact that less than one in five Mexicans has already accessed its full schedule.

Alejandro Macías Hernández, specialist in internal medicine and infectology and in charge of the AH1N1 influenza pandemic in Mexico for more than a decade, points out that the vaccination strategy that, as in most of the world, has left the younger groups at the end, can be one of the causes of this differential increase in infections. “The immunization effect is now seen in those over 50 years old, without a doubt that plays a role in the number of people we see and in which young people are the most infected now,” he says.

The contagion curve for those under 30 is effectively the steepest, already close to levels of the second (and highest so far) peak that the country has suffered; January of this year.

The fact that young people are not seriously ill does not reduce the seriousness of the number of patients in the country. While the incubation time can range from six to nine days, it implies that this age group can continue to infect older people.

“The worrying thing,” says surgeon Armando Rosales Torres, a former doctor at the General Hospital of Zone Number 1 in the State of Zacatecas, “is that measures are not being imposed to reduce the mobility of the youngest.” The effect of these measures would possibly be relative after a year and a half of intermittent impositions that have put the life of an entire generation on hold, in turn leading to mental health impacts whose true significance is yet to be discovered.

Furthermore, the younger age groups also take on their own bodies potentially serious consequences of an infection. Although until now the medical and media focus has been on the most serious derivation of covid, death, there is still much evidence to be collected regarding its long-term effects on people who overcome it. In countries with high accumulated impact, as is the case of Mexico, a gradual and difficult-to-predict emergence of varied sequelae can be expected, combined in turn with the prevailing comorbidities among the population.

The doctor Salvador Arteaga visits house-to-house patients with covid-19 in central Mexico, especially those who do not have social security. From Querétaro to Cuernavaca, this doctor has noticed the arrival of the third wave of coronavirus infections in the country. “I have had to attend more to young people, children and also adults over eighty years old regardless of whether they have the vaccine,” he says while moving to a town in the State of Hidalgo. The available evidence corroborates the effectiveness of any of the vaccines used in Mexico to reduce the probability of serious developments, but none of them completely prevents infection, and the improvement in defenses always depends to some extent on the starting conditions. As long as the virus has a high circulation capacity among people who still do not have access to the vaccine, the (now much lower) risk for the vulnerable will continue to be present.

One case especially caught the attention of Arteaga. A 21-year-old patient, with apparently mild symptoms, whose fever struck again five days after it had been controlled and without wanting to stop. “Although it behaves in a less aggressive way, the variants of covid in young people lead them to longer treatments,” says the doctor based on his experience. The 21-year-old has not required medical oxygen, but Arteaga does not rule out a higher wear and tear on his body.

Insufficient immunity, poor surveillance

When Mexico considered that the worst of the epidemic could be behind us, this third wave is reproduced thanks to the combination of an accelerated but still insufficient vaccination and the spread of virus strains that seek to penetrate the country’s still imperfect defense walls.

“The problem is that we do not have reagents to identify the type of variant that is being discussed, we can only rely on its symptoms,” says Rosales Torres. This is complex because there is still no solid evidence of a symptomatological difference between the new variants and the old ones, but there is the suspicion that at least Delta is contagious more efficiently. The follow-up of these new strains usually occurs with a detailed analysis of genetic samples obtained from patients with active or recent infection, but it is expensive and laborious, requiring financing and special equipment. The installed capacity of Mexico in this regard exists, but it is limited compared to the US or the UK, right now the largest sources of information on the variants.

Meanwhile, the contagion is re-sprouting in places that were considered practically immune thanks to the very high incidence of past waves, which (in addition to thousands of deaths) left in their wake antibodies and other defenses in those who surpassed them. But variants like delta are characterized by their ability to at least partially bypass this type of acquired immunity. Thus, Mexico City or Baja California Sur could see peaks like those that have already suffered; Quintana Roo or Yucatán would face perhaps higher growth due to high mobility in tourist areas.

The translation of these new regional peaks to hospital saturation is still pending analysis. Some entities with lower occupancy ceilings (due to space availability) could be in trouble in the medium term, but the levels remain far from the dreaded collapse today.

Whether this continues to be the case, as well as the translation of this third wave of infections into one of fewer deaths than the previous ones, depends essentially on vaccination. For now, around 16% of Mexican citizens have been able to have a complete immunization schedule with any of the available vials. The remaining 84% still depends on the protection that a single dose can offer (which, at least for the delta variant, seems to be notably less than that given by the two combined), or on the partial immunity that they have been able to acquire with previous immunizations .

The Mexican vaccination rate has set the average for Latin America. While Argentina or Brazil have been able to accelerate somewhat more (without reaching the speed of the smallest and richest Chile or Uruguay), Mexico has remained on a curve similar to that of Colombia or Panama: above the poorest Bolivia, Peru or practically all of its Central American neighbors, but below what many expected from the country that applied the first dose throughout Latin America, on December 24, 2020.

This third wave confirms that Mexico will not be able to consider that it has overcome the pandemic either after the inevitable valley of contagions that will arrive in weeks or months, as that of this last spring after the January peak. Not at least without a greater acceleration in the rate of vaccination, the only way to victory with which humanity has hitherto given in its fight against the virus.

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