The latest report from the Imperial College London shows that Brazil did not sustain the drop in Covid-19 transmission. The infection's effective reproduction number or transmission rate (Rt) - which gives an idea of the speed of contagion, which in recent weeks had slowed down for the first time in four months and was below 1 - increased for the week that began in day 16 (Sunday before last) to a level of 1, which means that each infected person is transmitting the disease to another person. This shows that Covid-19 is maintaining a relatively high speed of spread. A The situation had been stabilizing in the most populous states, such as São Paulo and Rio de Janeiro and in the North and Northeast. Commerce has begun to reopen, although still with some restrictions, while schools, theaters, cinemas and museums remain closed. The reopening of the economy and the relaxation of non-pharmacological measures could lead to an increase in the number of cases, as the population thinks that the pandemic is declining, which is not true. In fact, according to Monitor da Folha, the transmission of Covid-19 only decreased in 43% of municipalities with more than 100 thousand inhabitants, maintaining the growth rate in 57% of cities, considering data from the last 30 days. For us to have a real tendency for Covid-19 to disappear, the Rt index needs to be kept below 1, without upward fluctuations. Read more.
Check below a brief overview of thethe events of the last weeks. The report involves from the news about reinfections, a possible new medicine, community immunity and vaccines, to the new attacks on universities. Our knowledge about the pandemic is increasing rapidly, hence the need to seek information to combat misinformation.
REINFECTION IT'S POSSIBLE?
Recently, four people in China, Belgium, the Netherlands and the United States were confirmed as cases of SARS-CoV-2 reinfection. Last week, a study accepted for publication in the magazine Clinical Infectious Diseases, carried out by Hong Kong researchers, confirmed that a 33-year-old man, without comorbidities, after having a confirmed SARS-CoV-2 infection in March, was reinfected with a different strain of the virus, 142 days after recovering. Confirmation of reinfection occurred after the man was tested at Hong Kong airport, upon returning from Spain, via the United Kingdom. According to the researchers, there were significant differences in the genomes of the viruses that caused the two infections, which ruled out the possibility that they were the same virus. O The patient had the first infection with mild symptoms and, in the second infection, he was asymptomatic, which shows that his immune system protected him from getting sick, but not from being infected. In Belgium, a woman in her 50s contracted Covid-19 for the first time in March and was reinfected with a different strain of SARS-CoV-2 in June. Apparently, she produced few antibodies after the first infection, but the second infection was milder. The case of the Dutch patient is an older person, with a fragile immune system. The results of the cases of patients from Belgium and the Netherlands have not yet been published in scientific journals.
A new case of reinfection just 48 days old After the first infection, it occurred with a 25-year-old patient in the United States, who even had a more serious illness in the second infection, but has now recovered. Also in this case, genetic sequencing of the virus revealed that it had been infected with a slightly different strain, indicating a true reinfection. The data is available in the form of publication in prepress platform, still without peer review.
In the case of the Chinese patient, reinfection was confirmed by analyzes epidemiological, clinical, serological and genomic, involving genetic testing of the virus in the first and second infection, which showed a difference in 24 nucleotides, the building blocks that form the virus's RNA. This result suggests that the man was infected by two different strains of SARS-CoV-2, the first related to a variant of the virus circulating in the USA and England in March and April and the second, related to the strain circulating in Switzerland and England. in July and August. Similar results were obtained in patients from Belgium and the Netherlands.
These cases are different from other previously recorded cases, in which people continued to test positive for the new coronavirus for a few weeks, which was not caused by reinfection with a different strain of the virus, but by remnants of the virus's genetic material that remained in the body. It is necessary to carry out genomic analysis to confirm whether it is a new infection or not, as it may be a remnant of genetic material from the first virus, which it may still exist in patients' lungs but not be detected in samples taken from the upper parts of the respiratory tract.
People should not assume that once they are infected and subsequently cured, they will have lifelong immunity. Science knows that even if a person has had a mild infection, there is an immune defense response, although doubts remain about the duration of this response, whether it will prevent new infections or, in the case of reinfections, whether the symptoms will be milder.
We know that antibody levels in people cured of Covid-19 drop a few months after infection, but this is normal and the immune system not only relies on neutralizing antibodies (humoral response) to fight the virus, but also on cytotoxic cells. defense (cellular response, CD4 T and CD8 T cells). And we can also count on cross-immunity, protection developed by previous contact with other types of coronavirus. The fact that the reinfected Chinese man showed milder symptoms after the second infection is a good sign, because despite showing that the body's protection in terms of neutralizing antibodies did not prevent the virus from entering the body, T cells (cellular response memory), probably prevented the disease from progressing. This reinforces the idea that a good vaccine must induce not only an antibody production response, but also a cytotoxic cell response.
It is also a fact that the time between the two infections was very short. These facts could raise fears about the effectiveness of vaccine candidates in protecting us from Covid-19 and spark a warns that the immunity generated by previous contact with SARS-CoV-2 may not prevent subsequent infections, but it is still too early to alarm, as pwe need to look at this on a population level. It is important to know how frequently and to what extent these possible reinfections occur.
We have approximately 24 million people infected worldwide, so it is not surprising that we have some cases of reinfection and we will likely have others. People reinfect themselves with the viruses that cause the common flu, so we will certainly have reinfections with SARS-CoV-2. We cannot jump to conclusions and it does not seem to be a cause for concern at this time. SARS-CoV-2 is not very stable, it is constantly mutating, which is normal, but fortunately it is not becoming more virulent or more lethal.
If reinfections become frequent, it could mean that we are not producing a lasting immune response and it could mean that any vaccines are unable to induce a sufficient response so that our body has the capacity to respond to the new coronavirus, preventing an infection. But the fact that the second infection had reduced severity, as in the case of the Chinese patient, is very good and is what we hope to see with a vaccine. If reinfection is common, it could be an argument for vaccinating even those who have recovered from Covid-19.
It may be that a vaccine does not provide protection forever, but the The only effective way to create collective immunity will be with a vaccine and even people who have already contracted Covid-19 would have to be vaccinated. A vaccine produces a strong immune response, which, added to the body's natural response, will certainly protect us from Covid-19.
These cases could suggest that collective immunity may not be able to prevent the spread of the new coronavirus, as a person could become reinfected and continue transmitting the disease. It may be that a new infection could reduce the amount of virus that the infected person transmits to other people, but we don't know. So, another The crucial question is whether reinfected people can still spread the virus, because if they do not spread the virus, it will be the end of the transmission chain, a dead end for the virus.
The fact that reinfection is possible reinforces the need to maintain non-pharmacological measures such as the use of masks, washing hands, use of alcohol gel and maintaining the rules of physical distancing and social isolation even among people who have already had Covid-19. For an interesting article on this, em that symptomatic and asymptomatic SARS-CoV-2 reinfection can occur in the presence of IgG antibodies against SARS-CoV-2, see here.
NEW MEDICATION ON THE SCENARIO – AMODIAQUINE
Amodiaquine (AQ) is an antimalarial drug used to treat uncomplicated malaria, more effective, more palatable and less expensive when compared to chloroquines. However, due to reports of adverse effects observed in patients who used the drug prophylactically in the treatment of malaria, AQ is not used as a first-line drug. This drug has already been used unsuccessfully to combat the SARS virus and Middle East Respiratory Syndrome. A job involving Computational studies suggested that amodiaquine would be a potential MPro protease inhibitor of SARS-CoV-2. An article published on 19/08/2020, in online platform, without evaluation by other scientists, showed results of inhibition of SARS-CoV-2 vitro e in vivo with the drug amodiaquine. amodiaquine has been testeda em hamster by researchers from Icahn School, in New York, who received doses of the drug for 4 days and was tested in hamster infected by the protein new coronavirus and others hamster uninfected. The researchers recorded that there was a 70% reduction in the genetic material of the virus in the lungs of infected animals, compared to animals that were not medicated. A second stage of the study involved hamster medicated with amodiaquine and hamster unmedicated, but infected with SARS-CoV-2. The animals were placed in the same cage. The observed result was that 90% of hamster medicated patients had less genetic material from the virus in their lungs.
This study in hamster, however, it cannot be extrapolated to humans and there is no evidence to justify its use in humans without first undergoing randomized, double-blind, placebo-controlled clinical studies. It is known that amodiaquine can interact with various cells in our body. Common side effects include loss of appetite, nausea, abdominal pain, drowsiness, difficulty sleeping, coughing and depending on the dose, cardiac arrhythmia. Due to its slow renal clearance, amodiaquine can concentrate in the liver. The medication should be used with caution in people with liver disease or alcoholism and in patients receiving hepatotoxic medications. Children are especially sensitive to 4-aminoquinoline derivatives and caution is needed because of the narrow margin between therapeutic and toxic concentrations in children.
PANEL VACCINES COVID-19
- The growing manti-vaccine movement
The spread of fake news about Covid-19 produced by anti-vaccine groups on Facebook has increased considerably, according to studies da UPVaccine Pro-Vaccine Union, a group linked to USP Ribeirão Preto and the activist group Avaaz. Although the movement of anti-vaccine groups is not as strong in Brazil, the political-ideological polarization, mainly involving issues in the area of health, is awakening the voices of vaccine deniers in the country, who have already covered everything from conspiracy theories to the possibility that vaccines cause abortions. However, recent research by Datafolha showed that if a safe and effective vaccine against the new coronavirus is developed, 89% of people intend to get vaccinated. Initiatives such as “do it yourself” RaDVac, an acronym in English that means a collaboration for rapid vaccine development, can contribute to public distrust in relation to Covid-19 vaccines and merited an editorial in the prestigious Science magazine. For more details read the article in the magazine Science Question.
- Candidates of phase 3
We currently have 3 vaccine candidates in phase 3 clinical trials: the one developed by the University of Oxford and the company AstraZeneca, with 5.000 volunteers, that of the Chinese pharmaceutical company Sinovac, with 9.000 people being tested and that developed by Pfizer, being tested on 1.000 volunteers. The Butantan Institute will receive R$82,5 million from Fapesp and Todos pela Saúde (Itaú Unibanco) for the development of phase 3 clinical trials of the Coronavac vaccine candidate. Regarding the vaccine candidate being developed by the University of Oxford and the AstraZeneca laboratory, the researchers leading the tests in Brazil requested authorization from Anvisa to include volunteers over 69 years of age. To start phase 3, we also have Russia's vaccine candidate (Sputinik IN), which the Paraná Institute of Technology (Tecpar) intends to test on at least 10.000 volunteers starting in 45 days. The Government of Paraná claims to have received information on the results of phases 1 and 2, which are still in the translation and analysis phase. Russia, which is quicker to trigger than the Ranger Tex Willer, is preparing to approve a second Covid-19 vaccine in early October. This second vaccine candidate is being developed by the Russian State Research Center for Virology and Biotechnology (Vector) in Siberia. This week, the agreement to test a fifth vaccine candidate in Brazil was also announced, which is being developed by Janssen, the Johnson & Johnson pharmaceutical company. Phase 3 will involve around 7.000 volunteers at two dozen research centers in several states.
- After all, what is Collective Immunity
In Brazil, apparently, Rio de Janeiro, Manaus and São Paulo present some positive signs that they have achieved the so-called collective immunity (I prefer to use this term rather than herd immunity). This would be achieved when the spread of the new coronavirus is reduced, when the spread loses strength, because there are not enough susceptible people to sustain an epidemic. MWhile this does not mean that the risk of spreading SARS-CoV-2 will not remain high, we need to expect a sustained drop and continued slowdown in the number of cases for at least 30 days. Reducing the rate of spread is very important and desired, but we need to be cautious and avoid an increase in the rate of acceleration due to the relaxation of non-pharmacological measures to restrict and contain the new coronavirus. However, the emergence of cases of reinfected people, if it becomes frequent, could make it difficult to reaching group immunity lasting, whether through the protection generated by recovery from the disease or that generated by vaccines.
LEARNINGS OF SCIENCE IN TIMES OF PANDEMIC
Um published report recently in the magazine Anesthesia, involving 24 studies and just over 10 thousand patients admitted to ICUs in Asia, Europe and North America, showed a reduction from 60% to 42% in the mortality of critically ill patients Covid-19 between March and May. Among the factors responsible for reducing mortality are the use of medications such as the corticosteroid dexamethasone, the anticoagulant heparin, broad-spectrum antibiotics to combat bacterial infections and learning about various techniques in the areas of health. Compared to the beginning of the pandemic, today patients are better cared for and the full ICUs and the sharing of information have led to great learning. Science helped save lives as more became known about the disease. Revised medical practices include not carrying out early dialysis in patients with kidney problems, as many recover without dialysis. Another change was not to intubate critically ill patients with a drop in oxygenation rate early, preferring to adopt non-invasive ventilation, as it was discovered that intubation brings additional risks to patients with Covid-19, such as bacterial infections and lung damage. Another strategy that was successfully used was the prone position, when the patient, even those who are conscious, is turned face down to improve lung oxygenation. Another very important point is the understanding that Covid-19 needs a multidisciplinary team, requiring professionals from various areas, as it affects organs such as lungs, heart, kidneys and brain.
- Scientific divulgation
There is no doubt that communication and dissemination of science to society are extremely important to combat misinformation and a way to democratize access to science. Society understands that it needs science to effectively combat the pandemic, but we need to get qualified and reliable information to people. We are seeing science in evidence in the media, but we are also seeing pseudosciences occupying noble and firm spaces on social networks, and we know that disinformation networks spread faster than scientific information reliable and quality. Disinformation is a global phenomenon, but particularly in Latin America, where government leaders have resorted to dangerous promises of miraculous cures.
Researchers and scientists are demanding revisions to the Bill to combat fake news, PL 2.630/2020, requesting other forms of redress such as the right to reply, retraction and distribution of information, in addition to the payment of fines. One suggestion is the platform's obligation to distribute the retraction or correction of true information from independent and reliable sources to all users who were exposed to content/behavior that violates the law and terms of use.
- Future of science
At this moment, the future of science in Brazil is threatened and in the State of São Paulo it is in the hands of parliamentarians of the Legislative Assembly. With all this going on, we can't stay in the square, feeding corn to pigeons. Neither us nor anyone else, as dear professor H suggestsernan Chaimovich in his recent article in the magazine Science Question.
Note: This text does not necessarily reflect the opinion of Unicamp.