Coronavirus in Mexico: cases are up 233% because it's cold outside

Since the first coronavirus case was confirmed in 2020, 7,145,409 cases and 330,592 deaths have been attributed to Covid-19 in Mexico.

Coronavirus in Mexico: cases are up 233% because it's cold outside
Vaccination campaign against COVID-19 is being carried out in Mexico. Photos: UNAM

Between October 30 and December 3 of this year, COVID-19 cases have risen by 233% in Mexico, according to data from the Ministry of Health. During the 44th epidemiological week, which runs from October 30 to November 5, 3,496 new cases were registered in the agency's Epidemiological Bulletin. Infections rose to 11,653 in week 48, which covered from November 27 to December 3, 2022, according to data from the Conacyt board.

"A sixth wave is forming and has particular characteristics because it is a sixth wave that is configured with inflections of different pathogens: COVID, of course, influenza, and respiratory syncytial virus, especially," said Dr. Samuel Ponce de Leon, coordinator of the University Program for Research in Epidemiological and Emerging Risks of the UNAM, in an interview.

A cold season with many cases of respiratory diseases is expected because for three years strict prevention precautions were maintained, which reduced the possibility of exposure to respiratory viruses. "We are going to have a very raw season, one that is very serious, of respiratory infections in general." With the resumption of face-to-face activities and the relaxation of sanitary measures, the population is once again exposed to respiratory viruses that circulate in the cold season.

Since the first case was confirmed in February 2020 and to date, there are 7 million 145,409 total cases and 330,592 total deaths in Mexico due to Covid-19. Unlike other times of the pandemic, new infections are currently predominantly among women, with 53.2%, and an average age of 38 years. While 62% of confirmed deaths have occurred in men, with a median age of 64 years.

As of December 5, 2022, Mexico had 13,722 active cases and an incidence rate (new cases) of 10.5 per 100,000 inhabitants. Mexico City is the state with the highest number of active cases to date, with 3,604. It is followed by Quintana Roo, with 1,377; Yucatan, with 1,204; State of Mexico, with 940, and Chihuahua, with 791.

Covid-19 variants in Mexico

For now, almost half (45%) of the COVID-19 cases reported in the country are caused by the Omicron BA.5 subvariant. BW.1, a sublineage of Omicron that may have emerged in Yucatan, is already responsible for 19% of the new infections, according to the latest SARS-CoV-2 genomic report, published on November 17 by the General Directorate of Epidemiology.

However, BW.1, also called Xibalba, was not yet considered a subvariant of Omicron under monitoring by the World Health Organization (WHO). In terms of the increase in COVID-19 cases, the expert Ponce de Leon added that projections indicate that the sixth one would not be as serious as the previous ones. However, he stressed, there will be hospital demand, and, for this reason, the scenario is worrisome.


Given the increase of COVID-19 and other respiratory diseases, Dr. José Luis Sandoval, a pulmonologist and expert in critical medicine, recommended the continued use of masks in crowded places and frequent hand washing. to stay at home if you have the flu to protect yourself and others It is essential to get vaccinated against COVID and influenza because, although these doses do not prevent respiratory infection, they do help to make the disease more benign.

Why is it important to use masks?

The use of masks in open and closed spaces was implemented following the start of the COVID-19 pandemic; however, even though cases of this virus in Mexico have been decreasing day by day, this habit must be maintained in the event of the presentation of any respiratory disease. Experts assure us that 80% of the transmission of diseases, including COVID-19, arises through the nose and mouth, so using a mask is a great defense measure to avoid contagion.

Coronavirus vaccination campaign is carried out.
The coronavirus vaccination campaign is carried out.

Vaccination against coronavirus

Vaccination is the main way to prevent a person infected with the virus that causes COVID-19 from becoming seriously ill and having a greater probability of requiring hospitalization or death. As a result, we emphasize the importance of all people over the age of 15 starting or finishing their vaccination schedules and receiving their booster dose as soon as it is due. All vaccines used in Mexico are safe, effective, and of high quality. Although there is no information on each of the combinations, studies that have evaluated schemes where different vaccines are combined, both to complete initial schemes and booster doses, have found them to be safe and effective strategies.

Face masks

The main way the COVID-19 virus is spread is through aerosols produced by a person infected with the virus (with or without symptoms) and formed by breathing, talking, coughing, sneezing, blowing, shouting, singing, and wheezing. The use of a facemask reduces (filters) the amount of virus exhaled by an infected person and limits the amount of virus inhaled by a person nearby.

The general recommendation is that everyone should wear a mask covering the nose and mouth when living with sick people when being in public places outside the home, and when being with other people in closed places or even in open spaces if the distance is close. Even when using masks, it is not advisable to talk closely with other people. There is misinformation and confusion about face masks, but the most important thing is to use one that is comfortable and accessible for its correct and continuous use. The important thing is to use a useful mask and not a perfect mask.

If a cloth mask is used, it must have three layers and be made of natural fiber (cotton); if the mask is a disposable surgical mask, it must also have three layers. Their efficiency can be measured if they prevent the passage of light.

The most efficient masks (N95, KN95, KF94, FFP3, FFP2, FFP1) are best used in situations where the risk of aerosols from patients is greater, such as when caring for a sick person at home, in a doctor's office, or the hospital. The limited availability and discomfort of these types of masks can be real obstacles to their general use, and they are not suitable for common use, generating additional risks if used inappropriately or interrupted.

Successful prevention in the use of nasal covers is achieved through their proper use. Whichever one is used should cover the nose and mouth at the same time and be adjusted to the bridge of the nose and to the skin of the face without folds, to avoid the free entrance of air through the corners of the mouth. In case you decide to use a double mouthpiece to increase protection, it will be better to combine mouthpieces of two different types of materials and place the most efficient one first and then the less efficient one on top. Once it is in place, avoid touching it from the front, remove it by the adjustable straps and wash your hands after doing so.

About COVID-19 coronavirus

In December 2019, a series of cases of pneumonia of unknown cause emerged in Wuhan, Hubei, China, with clinical presentations closely resembling viral pneumonia. On January 7, 2020, the etiologic agent responsible for this picture was identified as a new betacoronavirus (SARS-CoV-2), distinct from SARS-CoV (2003) and MERS-CoV (2012), and the disease is referred to as COVID-19. Undoubtedly, this new virus is the first pandemic of the 21st century that has come to permanently alter and transform the daily, economic, political, and social life of the world. The disease spread to the countries of the region: Thailand, Hong Kong, South Korea, Japan, and later to Iran, Italy, Spain, and the rest of Europe. In America, it appeared initially in the state of Washington and with greater intensity in New York and the rest of the American Union.


Diagnostic methods are primarily molecular: PCR (polymerase chain reaction), which detects the genes of the virus E gene for screening and RdRp gene for confirmation, which is not only specific but also very sensitive if the sample is taken properly, and methods based on the detection of IgG (past infection) and IgM (active infection) antibodies, which are marketed as rapid tests due to the short duration of the procedure, but they do not guarantee an immediate diagnosis because the antibodies are detected after

Clinical Presentation

From the clinical point of view, in the beginning, only respiratory symptoms, fever, and general malaise were mentioned, and it was erroneously thought that 1% of people were asymptomatic, when in fact 35 to 40% of people have no symptoms, which help the spread of the virus by not being detected if the corresponding studies are not carried out. Fortunately, in 80% of those who present symptoms, the disease is self-limiting, but 15% require hospitalization, and 5–6% require intensive care units for mechanical ventilation and comprehensive management of critically ill patients.

The clinical spectrum also includes alterations in the nervous system, such as cerebral and heart infarcts, which produce carditis and arrhythmias; in the skin, vesicular lesions in the extremities; in the kidneys, where 15% of hospitalized patients develop kidney failure, and in a fraction of these, the damage is permanent, requiring hemodialysis; there is also loss of smell and disseminated intravascular coagulation, and a whole clinical spectrum yet to be defined. In the pediatric population, which until recently was considered immune or with little impact, a syndrome similar to Kawasaki disease is now recognized, which is severe and requires hospitalization and has even caused some deaths.

Sources: daily and weekly updates from Hugo Lopez-Gatell, Mexican Undersecretary of Prevention and Health Promotion, Ciencia UANL (102), by Javier Ramos Jiménez and Ana María Rivas Estilla