It’s useless to wear a mask. Tests are the key to ending confinement. People who had coronavirus are immune to infection. Children spread the virus. The epidemic will end by summer. All these points have been challenged one after another within weeks of them coming out. Why such discord?
Although scientists who are supposed to give objective advice have infiltrated television sets and websites, we are still plagued by conflicting views and figures on the COVID 19 epidemic. Immunity, masks, mortality, testing… Never before has science produced so many studies in such a short time and never before have they seemed so contradictory. I am not sure that flooding the Internet with facts and scientific data’ is the best way to combat fake news, as the UN Secretary-General suggests.
Asymptomatic patients: How many are there?
“With the flu, infected but asymptomatic people are important transmission factors, which seems not to be the case with Covid-19. Chinese data show that only 1% of reported cases are asymptomatic and most develop symptoms within two days of infection,” said the WHO Director-General on 3 March. This figure was subsequently drastically revised upwards. According to a BMJ article published in April, four out of five infected people are declared asymptomatic. Studies show that the figures vary greatly between 4% and 70%. A study in US prisons shows that 96% of cases are asymptomatic. The reality is that nobody knows about this, so it is impossible to know how many people are already affected.
Immunity: are you protected when you recover?
A person infected with the coronavirus usually develops antibodies that can prevent reinfection. Based on this assumption, many doctors have developed the concept of “herd immunity”, which means that the epidemic can only really be stopped when 70% of the population is infected and therefore protected. Since then, however, doubts have arisen. “Some of the people who have recovered from Covid-19 have very low levels of antibodies in their blood. There are no studies to determine whether these are sufficient to prevent new infections,” warns the WHO. In addition, not all antibodies are able to neutralize the virus. According to a Chinese study, 30% of cured patients developed very small amounts of neutralizing antibodies. However, “it is not known whether these patients with a low neutralizing antibody titer have a high risk of rebound or reinfection,” notes the High Health Authority (HAS). There is also uncertainty about the duration of vaccination: three months? One year? Several years?
Confinement not a long term solution
According to a study published in March by Imperial College London, containment could have prevented up to 120,000 deaths in Europe. Another study by the École des Hautes Etudes en Santé Publique mentions 60,000 lives saved in France alone. Apart from the fact that the few countries that have not taken rigorous measures are doing quite well. Sweden, for example, only registers 3 175 deaths, compared with more than 26 000 in France. Other experts even believe that containment could have more negative than positive effects, discouraging chronic patients, or stroke victims from going to hospitals. A member of the British government, quoted by the Financial Times, regretted that “all the eggs were put in the same basket [by Covid-19] instead of seeing the overall impact on health”. Doctors are also alarmed at the long-term psychological consequences of confinement. Not to mention the economic effects that will push many people into poverty.
Mortality rates: alarming or insignificant?
On January 21, an article in the Journal of Medical Virology calculated the mortality rate for the new coronavirus at 9.6%. Fifteen days later, the WHO has already revised the rate down, pointing to a mortality rate “ten times higher than the flu”, with 3.4% of deaths among Covid-19 patients. As the pandemic has spread and according to national statistics, the pandemic has changed constantly.
In France, there are 26,000 deaths in 175,000 cases, corresponding to a mortality rate of around 14.9%. In China, however, it is 5.6%, in Germany 2.7% and in Singapore 0.1%. A Stanford University study revealed a mortality rate of between 0.12% and 0.2%, with some experts even assuming 0.04% – less than for influenza. All these figures are based on the hypothetical number of people infected, which in turn depends on the number of tests performed or poor extrapolations.
Screening tests: indispensable or useless?
“Deconfinement will trigger a new wave of infections unless a massive policy of testing and isolating infected people is put in place,” an Inserm study said in April. “The objective is clear: testing, testing, testing,” added Olivier Véran on March 25. Presented as key to the success of certain countries like Germany in containing the epidemic, the usefulness of testing is now being questioned because of its unreliability. Some serological tests have a 40% rate of false negatives (people who produce antibodies that are not detected). On 2 April, the Haute Autorité de santé (HAS) recommended caution in the use of serological tests for issuing an immunity passport. “We still do not know reliably what protection antibodies offer to people previously infected with the virus,” explains Dominique Le Guludec, president of HAS, “which led us to exclude the tests in the general population.”
Seasonal effect: will the virus disappear this summer?
“Until April or during the month of April, the heat usually kills this type of virus,” Donald Trump said on Feb. 11 about SARS-CoV-2. Since then, there has been a constant debate about whether or not the coronavirus is heat sensitive. Researchers were initially very cautious, pointing out, for example, that other coronavirus outbreaks, such as MERS, had spread to hot countries like Saudi Arabia. “In vitro, the virus reproduces very well in the heat,” Pierre-Marie Girard, Director of International Affairs at the Pasteur Institute. However, numerous studies have shown that the virus survives better in cold and dry environments than in hot and humid environments. On 24 April, Bill Bryan, director of the US Department of Homeland Security, reported the results of a study that “appears to show the strong effect of sunlight on the death of the virus, both at the surface and in the air”.
Wearing a mask: useful or counterproductive?
Are masks a crucial element in the fight against the spread of the epidemic or do they cause more harm than good? “The use of masks if you have not traveled to high-risk areas is not recommended because their effectiveness has not been proven,” was the moto in February. For its part, the WHO stressed that the use of a mask is useless for healthy people who are not carriers of the virus. Since then, many governments have changed their stance and are making wearing masks in public mandatory.
Children: are they very contagious?
Although it has been known since the beginning of the COVID 19 epidemic that children are in the minority among confirmed cases, their role in the spread of the epidemic is still contested today. For example, a study published in The Lancet states that ‘children are as susceptible to infection as adults’ and, although they develop fewer symptoms, ‘they have a similar risk of infection as the rest of the population’. In contrast, several studies suggest that children are less likely to spread the epidemic. “Children under 10 are probably less severely affected than adults, i.e. they are less susceptible to infection and less contagious,” said epidemiologist Arnaud Fontanet during a parliamentary hearing on 30 April. This may be due to a lower viral load or to the fact that they have fewer symptoms (e.g. they do not cough).