Coronavirus in Mexico: cases, vaccines, COVID-19 semaphore and latest news

Coronavirus in Mexico: The number of covid-19 cases increased by 5,755 during the last week, for a total of 5,739,680, while 200 deaths were added, reaching 324,334,334, reported the Ministry of Health in the Weekly Technical Report.

Coronavirus in Mexico: cases, vaccines, COVID-19 semaphore and latest news
Vaccination campaign against COVID-19 is being carried out in Mexico. Photos: UNAM

During the last week, the number of covid-19 cases increased by 5,755, for a total of 5,739,680, while 200 deaths were added, reaching 324,334,334, reported the Ministry of Health in its weekly technical report.

The agency specified that the number of active cases is 5,658, of which 1,624 were reported on April 26. It indicated that during the last five weeks, most of the cases are present in the 18 to 29 years age group, followed by the 30 to 39 years age group and the 40 to 49 years age group.

The Institute of Security and Social Services for State Workers (Issste) reported that as of May 1, 18 of the 32 states had no patients hospitalized for this cause. It indicated that the Institute's 114 medical units for covid care registered 10 admissions, 11 discharges, and two deaths in the last 24 hours.

Coronavirus vaccination campaign is carried out.
Coronavirus vaccination campaign is carried out.

Vaccination

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 and death. Therefore, we reiterate the importance for all persons over 15 years of age to initiate or complete their vaccination schedules and receive 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 the 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 by 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.

Handling the sick at home

The vast majority of people who have become ill with COVID-19 in recent weeks have presented mild symptoms that generally resolve in less than five days with general care and medications to control fever (paracetamol) and discomfort due to the body's response to the infection (ibuprofen). Due to the above and to avoid risks of toxicity or complications, it is important to reiterate that for the management of patients with COVID-19 the following should not be used:

Antibiotics of any kind (azithromycin, levofloxacin, ceftriaxone, ivermectin, hydroxychloroquine, etc.).
Antivirals that have no effect against the virus causing COVID-19 (oseltamivir, amantadine, rimantadine, acyclovir, etc.).
Steroid medications in the first five days of illness (cortisone, dexamethasone, etc.).
Anticoagulants without medical supervision (aspirin, heparin, enoxaparin, clopidogrel).
If the person suffers from any other disease for which he/she takes medications regularly, he/she should continue to use them without interruption.

When having a sick person at home, infection of the other inhabitants of the house should be prevented by isolation, the use of masks (ideally of high efficiency), ventilation by opening doors and windows, and regular hygiene with the products normally used in the place. To monitor the evolution it is advisable to have a thermometer to measure the temperature (not higher than 38.0ºC) and a pulse oximeter to monitor oxygenation (not lower than 92%). High temperature or low oxygenation should be reported immediately to your physician. Oxygenation should be monitored under medical supervision (with an oximeter) until you are sure that the evolution is favorable.

Once the person ill with COVID-19 has completed five days of isolation and has no symptoms, he/she may return to his/her activities with the general precautionary measures; if symptoms persist, he/she should complete ten days of isolation. Household contacts of the ill person should also remain in isolation for five days, at the end of which they may leave if they are symptom-free.


About COVID-19

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), 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.

The virus

Coronaviruses are enveloped viruses with a positive polarity RNA genome belonging to the coronaviridae family and the order Nidovirales. These viruses are widely distributed in humans and other mammals. SARS-CoV-2 has a genome of about 30,000 nucleotides and consists of four genes for the characteristic structural proteins of coronaviruses that are designated by the letters S (glycoprotein homotrimer whose distal widening of its folds forms the tips of the surface), E (small envelope protein), M (matrix protein linking the envelope to the viral core) and N (nucleocapsid phosphoprotein), in addition to ORFs (open reading frames), which encode nonstructural proteins, including enzymes that appear during its intrahospital reproductive cycle. The size of SARS-CoV-2 virions is approximately 50-200 nm in diameter. The complete genomic sequence of this new agent is available and different qualitative and quantitative detection protocols have been developed to understand the pathophysiology of the disease.

Although most human infections are mild, epidemics of the two beta coronaviruses, severe acute respiratory syndrome (SARS-CoV) and the Middle East respiratory syndrome (MERS-CoV), caused more than 10,000 cumulative cases in the past two decades, with the lethality of 10% for SARS-CoV and 37% for MERS-CoV. The coronaviruses that have been identified to date may represent only the tip of the iceberg, with potential new and severe zoonotic events yet to occur.

Pathophysiology

The immune response with which the human being defends himself is both humoral, forming antibodies, and cellular, mediated by lymphocytes. In patients with advanced disease with respiratory failure and multiple organ failure, it has been found that they are suffering from a cytosine storm, and in fact, some treatments in these advanced cases are based on using monoclonal antibodies against cytosines.

Diagnostics

Diagnostic methods are mainly 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, it is also very sensitive if the sample is taken properly, and methods based on the detection of IgG (past infection) and IgM (active infection) antibodies, These are marketed as rapid tests, because of the duration of the procedure, but it does not mean an immediate diagnosis, since they will be positive until after a week after the onset of symptoms, which makes them insensitive, giving false negatives if taken in the first days of symptoms.

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% were asymptomatic, when in fact 35 to 40% of people have no symptoms and these 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 to 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, producing carditis and arrhythmias; in the skin, vesicular lesions in the extremities; in the kidneys, 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, 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.

Treatment

The treatment consists not only of an antiviral drug, but also of integral management of each case since it is necessary to hydrate with serum and electrolytes, medication with vasopressors for those with low blood pressure, anticoagulants, and mechanical ventilatory assistance for the subgroup that can no longer breathe on their own, that is why even if there is no effective antiviral, patients can survive if they receive adequate care, and the earlier the patient goes to the hospital, the better their prognosis. So far there is no effective and safe antiviral treatment.

One of the most promising, according to recently published studies, is remdesivir, and one of the most used initially, which studies have shown to be not only ineffective but also dangerous, due to side effects, is hydroxychloroquine, with or without azithromycin, therefore it is not recommended. The use of plasma from people who have overcome the disease has also been tried; the first studies did not show a decrease in mortality, apparently because it was administered in very advanced stages, but now attempts are being made to administer it in earlier stages.

Prevention

Among the measures that have proven to be effective in controlling the spread of the virus is social distancing, in which people are asked to stay at home so that the virus does not find susceptible people and does not massively saturate hospitals, as has already occurred in Italy, Spain and New York; also effective is the use of protective masks, frequent hand washing and avoiding sneezing or coughing in front of other people.

However, for social distancing to be effective, it must be implemented early, as its effectiveness diminishes considerably if it is deferred for one or two weeks. Unfortunately, what has been achieved is threatened by an early opening of isolation due to economic and political pressures, without taking adequate precautions such as having sufficient tests and personnel for contact tracing with the possibility of having outbreaks that would force new, stricter isolation, which would result in greater economic and social damage.

SARS-CoV-2 Vaccines

The purpose of a vaccine is to "train" a person's immune system to generate a response to fight the virus and prevent disease. All vaccines aim to expose the body to an antigen that will not cause disease but will elicit an immune response that can block or kill the virus if a person becomes infected. Conventional approaches used to do this usually focus on the use of live attenuated viruses or inactivated or fragmented viruses. At least eight types are being tested against coronavirus, which is based on different viruses or viral parts.

Vaccine mRNA-1273-Moderna Therapeutics (United States): this vaccine involves molecular biology strategies. It is based on a messenger RNA that will produce an antibody response against the surface protein (S).

Vaccine INO-4800-Inovio Pharmaceuticals (United States): involves a design of direct injection of DNA through a plasmid (a small genetic structure) so that the patient's cells produce antibodies to fight infection.

AD5-nCoV vaccine-CanSino Biologics (China): This vaccine uses a non-replicating version of adenovirus as a vector. It carries the S protein gene (spike) from the surface of the coronavirus, which is intended to elicit the immune response to fight infection.

LV-SMENP-DC vaccine from the Geno-Immune Medical Institute in Shenzhen (China): an approach focused on the use of dendritic cells modified with lentiviral vectors.

Inactivated virus vaccine (China): this type of vaccine requires producing virus particles in reactors and then purifying them so that they lose their ability to cause disease. It uses common classical technology and is the most experienced production platform in vaccine production.

ChAdOx1 vaccine (United Kingdom): recombinant vaccine using as a vector an attenuated version of a chimpanzee adenovirus that has been modified so that it does not reproduce in humans.

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