Phase III study of Pfizer's immunization candidate begins, after completion of Moderna's study with pending efficacy adjustments against influenza type B
The last phase of the clinical trial of one of the two influenza vaccines developed with mRNA, the same platform as the last Covid-19 vaccines that entered the country, is starting in the country. It is estimated that in Argentina between 1,500 and 2,000 people over 65 years of age will participate in the new study, while in the United States research is progressing in young adults.
"Vaccines against respiratory viruses have always had a relatively low efficacy with respect to the new platforms, but that is useful for public health strategies to protect the vulnerable population. Now, the aim is to have vaccines with greater efficacy and rapid adaptation [to circulating strains] from year to year. It is a new generation of vaccines," commented Gonzalo Pérez Marc, principal investigator of the study that is being initiated at the Hospital Militar Central, together with several other centers in the city of Buenos Aires and one in La Plata.
In this case, it is the candidate vaccine for seasonal flu from the Pfizer laboratory. The first mRNA platform vaccine to be tested in phase III -prior to the application for regulatory approval for its commercialization- was Moderna's immunizer: in persons over 18 it showed efficacy against the circulating strains of influenza A, but not B, for which reason the laboratory informed last February, when communicating the results, that it would adjust the product to improve the immunological response.
Pérez Marc explained that, during the clinical trial that is beginning with the enrollment of volunteers, one group will receive the vaccine under evaluation and the other a tetravalent vaccine already on the market. The study design foresees that the participants and the researchers will not know until the end of the process to whom one or the other vaccine was randomly assigned.
It is a study in which the new product will be compared with an already available influenza vaccine. "The objective is to determine if the efficacy is the same as a product already approved and in use; if it induces the immune system to produce the same amount of antibodies against the circulating strains of influenza A and B virus," added the pediatrician, who is a senior researcher at the Military Hospital and general director of Equipo Ciencia, which is coordinating the study.
The requirements to volunteer are not many and include being in good general health, without an acute illness or an unstable or uncontrolled chronic condition. You also do not have to be vaccinated against the flu this year, but do want the annual dose. Those interested can register at https://www.equipociencia.com.
"The population over 65 years of age was very much affected by Covid-19 while there were no vaccines and, later, with prolonged Covid, so the focus in the world in the coming years is on this population, which at the same time has gained more quality of life and can be offered protection through vaccination," said Pérez Marc. Respiratory viruses have a great influence on cardiovascular complications and morbimortality," he added, by way of example.
At the same time, he anticipated that in the first half of next year, progress could be made with the trial of the combined vaccine for influenza, SARS-CoV-2 and respiratory syncytial virus (RSV), which are currently circulating.
Cocirculation scenario
In this scenario of triple circulation, as LA NACIÓN has been publishing, flu cases are beginning to displace RSV infections, with a small increase in SARS-CoV-2 infections, according to the testimonies of professionals in hospitals in the metropolitan area of Buenos Aires (AMBA) and the positive results for respiratory viruses under surveillance in the monitoring units designated in health centers in the provinces.
Nearly one third (32%) of the outpatient samples tested for the three viruses in these units were positive for influenza in the week of June 25 to June 1, according to the epidemiological report of the National Ministry of Health of this past weekend.
These three viruses alone are already causing more than half (52.5%) of respiratory infections. There are also cases of respiratory disease due to metapneumovirus, parainfluenza and adenovirus.
To this, the national health authorities added a public warning about an increase over previous years in detected cases of invasive infections caused by the bacterium Streptococcus pyogenesbacteria, better known for causing pharyngitis, angina or scarlet fever. In this case, the alert is not for these conditions, but for 118 cases of invasive forms of disease that can be caused by the same bacterium - such as meningitis, among others - without detection and adequate and timely antibiotic treatment.
In this regard, the Argentine Society of Pediatric Infectious Diseases (Sadip) issued a statement yesterday for health personnel in view of "data from different health care centers and the concern of [professionals] about the increase in cases of streptococcal infections".
In its recommendations, which are more oriented to pediatric care, the entity explains that invasive S. pyogenes disease is more frequent "as a complication of a previous skin and soft tissue infection (such as chickenpox, surgical wound infection, etc.), while pharyngitis as a gateway to invasive disease occurs in less than 20% of cases".
At this time of year, with the increase in consultations for respiratory causes, Sadip advises to suspect a pharyngitis by S. pyogenes pharyngitis to do a rapid test or diagnostic swab against children three years of age or older, especially school-aged children, with the following symptoms: sore throat and/or difficulty swallowing, fever, headache, abdominal pain, nausea and vomiting; redness and swelling of the throat, tonsils or uvula (uvula); petechiae on the palate, pharyngeal/tonsilary exudate, swollen neck nodes or adenopathy and appearance of reddish scarlet fever-like body rash.
