Coronavirus. Dr Oulhote: ‘this week will be crucial


INTERVIEW. The Moroccan Youssef Oulhote holds an engineering degree from the IAV Hassan II, a master’s degree in bio-contaminant risk analysis from AgroParisTech and a doctorate in epidemiology and public health from the EHESP . He is a research professor of epidemiology and biostatistics at the Massachusetts Public University and a research engineer at Harvard University School of Public Health.

The major risk that Morocco runs with this epidemic is a collapse of the public health system whose capacity is limited, in infrastructure, number of beds, human resources, bio-equipment … Developed countries like Italy have could not cope with the epidemic and that is why the measures taken should never be considered excessive.

The challenge today is to curb the spread to flatten the curve of the epidemic so as to spread the burden over time over the health system.

Youssef Oulhote: “We have no idea when we will return to a normal situation.”

Médias24: After about 4 months of spread around the world, what do we know about the coronavirus?

Dr. Youssef Oulhote: SARS-CoV-2 is a new virus, and we continue to learn about it every day. So far, scientific information has been changing very quickly. There are scientific articles every day and a unique collaboration.

All articles are available for free to encourage sharing of information in real time. Peer-reviewing [ndlr : évaluation par les pairs] is also expeditious for the same reasons. This is unique.

There are still many gray areas on the properties of the virus, probably with contextual differences from country to country. What we know at the moment, and which could evolve, is that:

* COVID-19 is transmitted faster than seasonal flu, with a basic reproduction rate of 2 to 2.5. This means that each infected person will transmit it on average to about two people. Some will do more, and others less.

* The incubation period is very variable, median of ~ 5 days, but may vary in cases. The majority would be between 2 and 14 days, but extreme cases exist and have been reported in China and Italy.

It’s also important to emphasize, 80% of cases will have milder or moderate symptoms and will not require special medical measures.

* Transmission would take place even before symptoms appear. There have been reports of this phenomenon with this new coronavirus, but it is not considered to be the primary means of spreading the virus at this time.

* The clinical symptoms the most commonly reported in laboratory-confirmed cases are: fever (> 80%), followed by a dry cough (~ 70%), fatigue (~ 40%), sputum production (~ 30%), dyspnea (~ 20%), sore throat (14%), headache (14%) and myalgia or arthralgia (15%).

* Estimates for the case fatality rate are not yet robust or reliable. Based on a large set of case data, the overall lethality risk (CFR) among diagnosed cases of COVID-19 in China, Italy and South Korea was 2.3%, 2.8% and 0, 5%, respectively, which is much higher than the seasonal flu (roughly 0.1%). However, we know that this figure will change and that we will not have a clearer idea of ​​this rate than towards the end of the epidemic.

Most importantly, this rate is variable according to age group. While it is around 0.02% in children, it can rise to 18% in populations over 80 years of age. The most frequently reported population groups with severe symptoms and death include people over the age of 60, men, people with underlying conditions such as hypertension, diabetes, diseases cardiovascular, chronic respiratory diseases and cancer.

* Cases may also be asymptomatic. The most reliable figures to date range from 1% of asymptomatic cases in Japan to 51% in the cruise ship in quarantine.

* The rate ofhospitalization is higher (around 20%). The healing time is also longer. For mild cases: from the onset of symptoms to healing, almost 2 weeks. For severe cases: from onset of symptoms to healing 3-6 weeks and from onset of symptoms to death 2-8 weeks.

Estimates of all of the above parameters should be revised and refined as more information becomes available.

The peak will be reached between the end of March and mid-April (Hubei scenario)

– The global epidemic will peak around what period? How soon do you think the world will return to normal?

-According to recent projections and risk analysis by the European Center for Disease Prevention and Control, the majority of EU countries would reach the scenario seen in Hubei in late March and all countries by mid- April 2020.

These forecasts should be interpreted with caution due to the assumptions underlying the models, including: 1) a diagnostic policy and stable capabilities, and 2) the absence of effective mitigation measures.

We must stop here for a moment to clarify that empirical modeling is not an exact science, however it is in the public interest because it allows us to estimate a set of scenarios and the uncertainties relating to these scenarios. We have no idea when we will return to normal. It is too early to know.

It is not even known yet whether the cured patients have acquired immunity or not, and how long this immunity would last. This will depend on whether we have other peaks as well.

A decrease in contagiousness is possible in summer but will not be sufficient

– Do you see an end to the epidemic in summer?

-It’s possible.

The short answer is that although we can expect the infectiousness of SARS-CoV-2 to decrease in warmer and wetter weather and perhaps with school closings, it is not reasonable to expect that these decreases in transmission due to the climate are sufficient to have a very great impact.

The regional comparison for the Covid-19 pandemic suggests some seasonality, but probably less than for influenza.

Changing seasons and closing schools may help, but it is unlikely to stop transmission.

The urgency of an effective policy is to determine whether children are important transmitters, in which case school closings may help slow transmission, or not, in which case resources would be wasted in such closures.

Previously, it was thought that children were not easily infected with SARS-CoV-2. Recent evidence from Shenzhen suggests that children can be infected at roughly the same rate as adults – so the only question is whether they transmit as easily. It seems likely that the answer is yes. And in this case, the government was right to close the schools as a preventive measure.

The great danger of the epidemic is that it saturates the already very low and fragile hospital capacity

– Apart from the economic and social impacts, in what way is this epidemic dangerous for the populations?

-The great danger for the majority of the population is not the virus in itself, except for the risk groups mentioned above.

The great danger is that it will saturate the hospital capacity which is already very fragile in Morocco.

The number of hospital beds in Morocco per 1,000 inhabitants is very low compared to countries that are already submerged by the virus.

Fortunately, the peak period of the seasonal flu is behind us, as it mobilizes a lot of hospital capacity.

The example of Lombardy, one of the richest regions of Italy is convincing. Hospital capacity is almost already saturated, and doctors are forced to make choices based on the probabilities of survival.

Not to mention that there is already a shortage of doctors and hospital staff in Morocco.

A growing number of cases imported from the EU and potentially local transmission chains which will most likely appear in the coming days will require many more resources, including staff for case management, surveillance, and contact tracing, which in some countries is starting or has already overtaken the public health system.

Communicating risks to the public and health professionals also requires significant and growing human resources. Another aspect to take into account is that there is the possibility of transmission among hospital staff.

– Do you think there will be a treatment or a vaccine this year?

-No idea. The virus has already been isolated, which would allow it to go a little faster. The broad collaboration of the scientific community is essential.

It must be said that the level of information we have today on the Covid-19, even if it is not complete, in just a few months is a performance in itself.

Several clinical trials for different pharmaceutical products and substances are underway. We will know more in the coming weeks. But in normal times, the marketing procedures are quite slow, and require a lot of testing and significant production capacities.

– What do you think of the attitude of the United Kingdom of favoring “collective immunity” without fighting aggressively against the spread?

– Collective immunity works when there is a substantial proportion of the population that is already immune to the virus, either by infection or by vaccination.

The idea is that we cannot contain the virus, so let it spread in healthy populations until we reach the level necessary for collective immunity.

I think this is a risky bet, since it will have to be avoided. There is currently no indication that it could work.

More than 200 epidemiologists and public health researchers have written to the British authorities in The Times asking the government to clarify the modeling assumptions behind this choice.

-Do you follow closely the evolution of the situation in Morocco?

-Of course.

There are no overly harsh measures. It is better to overestimate the impact

– Are the measures taken by Morocco too severe? justified? not severe enough?

-There are no harsh measures at this stage. I think that the measures taken are necessary to spare the populations at risk. It is best to overestimate the impact in these cases.

There is a very good cohort ofepidemiologists in Morocco. I hope you can get their opinions as well as they are in the field and will certainly have more details. They must be very mobilized at the moment and I wish them a lot of courage and also to the health personnel on the ground.

As a result, I think that the authorities in Morocco are more than aware of the situation and the burden that it could constitute for the already fragile health system, and act accordingly. Now, I think there should be a work of permanent communication with the public.

Is there a crisis unit, and who heads it … What measures have been taken in terms of coordination between the various ministries, administrations, etc.

It is a holistic work that requires permanent coordination and a very high level of preparation.

For example, are we ready if people ever have to work remotely? What digital infrastructure is available, what is the capacity to receive calls if we ever have a peak in the coming weeks?

And above all, how many tests do we have at our disposal? are we ready to test and monitor the populations concerned in the event of transmission clusters? how many beds we have, how many respirators and capacity in terms of intensive care …

These things may seem like details, but it is important to communicate them to the public.

Without drastic measures, Morocco risked going to tens of thousands of cases

-Depending on the number of cases in Morocco (28 this Saturday) and the restrictions adopted by the authorities, in your opinion how do you see the future of the epidemic in Morocco? will there be many cases? how much? what is the risk today? What should be done more or differently?

-I wrote an article with my colleagues from the Tafra Association and I was criticized for his alarmism. I admit that the tone is a little, but the situation is exceptional. Three days ago, before the government measures, there was a nonchalance, and the feeling of urgency was not palpable. We may be experiencing a major public health crisis, which will forever change how we manage the field of public health.

In the event of such a pandemic, it is necessary to see what the most extreme scenarios are, and to rely on them to prepare for the worst.

Again, empirical modeling is not an exact science, and one always prefers to be wrong than to underestimate the potential consequences.

I have put forward a figure of 2 to 4 million potential cases IF NO MEASURE IS TAKEN, this would correspond to more than 200,000 cases of hospitalization.

Almost no country can afford that. These figures are based on the transmission of the virus, data from the probable appearance of local outbreaks, and community transmission, but also on the similar case of the 1918-1919 flu. Similar scenarios exist everywhere. In the United States, it is estimated that the worst case scenario is that between 160 and 210 million Americans will contract the virus over a period of one year, with potentially 21 million hospitalizations.

Suddenly, the figure of tens of thousands of cases in the coming months cannot be excluded if there were no drastic measures, or if the measures taken are not effective enough. That’s why the measures taken by the authorities can never be described as excessive, it’s the right thing to do.

WHO advocates a comprehensive approach starting with diagnosis, tracing of cases and relatives, and quarantine, in addition to measures of social distancing. It is that the probability of an increase in clusters in local areas exists.

Today, we have a priori 28 confirmed cases. All but one are probably cases contracted abroad. So, for the moment, and officially, we have no community transmission, but that seems unlikely to me.

It is estimated that from 5 imported cases, the probability of community transmission is already 50%. Some of the cases cited in the press releases from the Ministry of Health have entered Morocco since February 24, 3 weeks ago. We do not have figures for the number of people in quarantine or the contacts of these people.

Have all contacts been traced, are they in quarantine, etc.

With the measures taken, the figures mentioned above will be revised downwards, but we do not have definitive data on the effectiveness of each measure to estimate a figure in the presence of a measure.

A study released this week gives some clues: In China, it is estimated that the number of cases would have been 67 times (between 44 and 94 in the majority of simulations) higher in the absence of the drastic measures implemented, including early detection , isolation of cases, travel restrictions and medical cordon.

Early detection and isolation of cases is likely to prevent more infections than travel restrictions and contact reductions, but the integrated approach would have the strongest and quickest effect. If these measures in China had been taken a week, two weeks or three weeks earlier, cases could have been reduced by 66%, 86% and 95% respectively, with a significant reduction in the number of affected areas.

The same study also suggests that distancing measures should be maintained for the next few months.

What is certain is that social distancing works.

If community transmission is confirmed, it will surely have to strengthen the measures currently

-What do you recommend to Moroccans?

-First follow the advice of the Ministry of Health and public authorities. The ministry’s site is really rich in details and advice. Consult the doctors if you have one, or if you know one …

Avoid spreading unfounded information across platforms. I also think that suspend Friday prayers and all gatherings would be a good idea.

The coming week is crucial, and we will have more information to see whether we need to introduce additional measures.

If community transmission is confirmed, the measures will surely have to be strengthened now. People will also have to show solidarity; plans will have to be made with neighbors and family to be able to organize themselves accordingly. Aside from that, all the usual stuff:

1. In case of suspicion, isolate yourself from the rest of the family, call the hotline without going to the hospital, unless the case worsens;

2. Avoid cafes, markets, and places with high population density;

3. Avoid traveling if it is not necessary.

4. Apply the usual hygiene measures;

5. Wash your hands regularly with soap,

6. Cover sneezing and coughing,

7. Open the windows to ventilate,

8. Wash the door handles daily,

9. Isolate those at risk, including the elderly, diabetics, cardiovascular, pulmonary, cancer, and immunodeficient patients.

10. If you have an air humidifier, use it, especially in dry areas.

11. Volunteering: If you can help, do it. Make a plan between neighbors to help each other, take turns shopping, etc.


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