Professor Lutsar: no sign of the coronavirus subsiding

The novel coronavirus has been circulating the world for seven months and there is no sign of it subsiding. This means, however, that we will very likely have to coexist with the virus for a very long time and it is up to humans, not the virus, to decide how we want or manage to do that, writes Irja Lutsar, Professor of Medical Microbiology of the University of Tartu.

Spread of and infection with the virus

In terms of the spread of the virus, countries can be divided as follows:

  1. Countries that had an intense wave of infections in February–April and implemented very strict restrictions which have now been relaxed. Despite high levels of infection, not more than 10% of the population has developed antibodies even in these countries (although there are large regional differences). There has now been a slight increase in infection in most of these countries (Spain, the UK, Belgium, the Netherlands), which have so far not led to an increase in mortality or the need for intensive care. It is too early to say whether it is because mainly young people are infected, or because the new wave has not yet reached a phase where mortality is rising, or because the increased numbers are due to more widespread testing. The curve is also significantly flatter. An increase in the number of the infected after the relaxation of the restrictions was expected and most experts and models predicted this to happen. At present, these countries are not rushing to introduce broader restrictions but rather emphasise the importance of social distancing and testing.
  1. Countries where the initial wave of infections was very modest or short-term. They show a significant increase in infections, which has so far not led to the overburden of the medical system. Examples include the Balkans, Israel, Australia, Singapore, Hong Kong, Luxembourg, Czechia, etc. This is unlikely to be a new wave, but the virus has always circulated in these countries. All these countries have reintroduced different restrictions, yet the infection continues.
  1. Countries where the spread started later than in most European countries and remains at a high level. In Russia, for example, around 5,000 new cases and around 100 deaths are reported every day. In the United States, the centre of infection has shifted from the East Coast to the West Coast and the South. Although the infection rate is in under control in some areas of the East Coast, the country-wide figures remain high. South American countries also fall into this category. No downward trend in infection can be noted yet, rather the rise continues.
  2. Countries where only a few cases of infection have occurred for a long time. This category includes predominantly islands or very small countries such as New Zealand, Vatican, Greenland, etc. Vietnam was also considered as such for a long time, but a significant increase in infections in the Danang region has also been observed in recent days. In Africa, infection remains low (except in the South African Republic).
  1. Countries I would like to highlight because of their specific nature:

a) Singapore – with very low levels of infection at first, the country now reports 300 to 500 infections every day for the third month already, while mortality is very low (0.05%). The infected are predominantly migrant workers. Singapore very well manages to monitor the infected and their contacts;

b) China and South Korea – the first outbreak was in January–February, but a small number of new infections still occur. Coronavirus has not disappeared from these countries;

c) Iran — the outbreak remains unchanged since February; every day around 2,500 new infected people and around 200 COVID-19 related deaths are reported. The restrictions are relatively modest and tend to be limited to the recommendation to comply with hygiene rules and wear masks indoors. Iran has reported that 20% of its population has antibodies against SARS-CoV-2. As infection steadily continues, it is probably not sufficient for the onset of herd immunity;

d) Sweden – a country that opted for lighter restrictions and which should not face any problems arising from the lifting of restrictions, as nothing has been lifted. In recent weeks, infections have notably decreased, despite a significant increase in the testing capacity. The number of fatalities and patients needing intensive care has also decreased significantly and over a longer period. The Swedish outbreak has lasted for around five months in total. Experts do not know exactly what is behind the current decline in infections – whether herd immunity is starting to develop or it is rather due to the holiday period and the related dispersion of people. The coming months will probably give us the answer;

e) Northern European countries and the Baltic states – the infection rate remains low, although a slight increase has been observed in all these countries in July. So far, the Nordic and Baltic states (excluding Denmark) have shown the lowest infection figures in Europe in terms of the number of infected people per 100,000 inhabitants over the past 14 days.


Since mortality rates are reported differently from country to country, cross-country comparison is not 100% reliable. What can be noted, however, is that case fatality rate varies greatly: from 0.05% in Singapore to 16% in France. Indeed, case fatality rates of more than 10% are mainly reported only in the most advanced Western European countries (Belgium, the UK, Italy, France, the Netherlands, Spain), while the world average is between 3% and 4%. All the countries mentioned above also report high mortality rates adjusted to population numbers. A detailed analysis of the difference in mortality between countries has not yet been published. It may be speculated that high mortality rates are due to an ageing population, an overburdened medical system or a low testing capacity, at least in the initial phase of the outbreak.

The infection fatality rate (IFR) is also considerably fluctuating, with low IFR (0.1%) in regions with low mortality rates, while the average rate was 0.27% in regions with high mortality rates. As expected, a notable difference between the IFR for people under 70 and over 70 can be noticed.

Prevention of SARS-CoV-2

As already mentioned, the levels of antibodies against SARS‑CoV-2 are low (<10%) in most regions of the world, even in countries with high levels of infection. There are some exceptions – northern Italy and the slums of Mumbai, where 50% to 60% of the population have antibodies. Since repeated infections have not been described so far, antibodies are likely to protect from repeated infection.

It is, however, too early to say how long this protection lasts. Thus, most of the world’s population is not immune to the virus, which is also proven by the constant circulation of the virus in most countries of the world.

Herd immunity could be induced with vaccines, but the arrival of vaccines on the market, despite the speed at which they are being developed, is not realistic in the coming months. More than 140 vaccines based on different methodologies are under development; five of those have entered the third-phase trials. Most of these trials only started and, even at a very high speed, we will not get the first results on immune response and vaccine tolerability before three or four months. Whether vaccines prevent the onset of COVID-19 among those vaccinated can be assessed in one or two years. Thus these results can be expected in summer 2021 at the earliest.

So far, low levels of infection have prevented third-phase trials. The current trials are carried out in countries where the infection is at its peak (the United States, Brazil, South African Republic, Saudi Arabia). It is noteworthy that the vaccines prevented both the serious disease and the infection in a small number of monkeys. So far, trials involving the infection of human volunteers have not been considered ethical. We do know that vaccines bring about neutralising antibodies in humans. Regulators have said that they accept a vaccine that is 50–60% effective. Thus, even if vaccines do reach the market at the end of the year, we will only know their short-term side effects and whether they produce antibodies, perhaps also their primary efficacy indicators.

Russian news channels have announced that physicians and teachers will be extensively vaccinated from October. The current understanding is that the vaccine developed by the Gamaleya Institute has not passed the third-phase trials. In conclusion, vaccines cannot be seen as a quick solution any time soon and non-pharmacological methods must be used to combat the virus. Physical distancing is an effective tool to prevent infection with infectious diseases (and not only COVID-19). This may become new normality, although it is not yet the case.

Masks are one method of social distancing and are probably the most important in a situation where physical distancing is not possible or where the number of virus carriers can be high (indoor spaces, public transport, hospitals). As this is primarily a human-to-human disease, wearing masks in places where there are few people or at a time when infection levels are low does not make much sense. Wearing masks is not dangerous if they are correctly used and regularly replaced. However, masks alone are not a magic bullet against the virus but are part of a complex set of measures.

Isolation is indicated only for close contacts of people infected with SARS-CoV-2 (>15 minutes closer than 2 m). Isolation should not be applied to the contacts of close contacts, as they do not pose a risk. Self-isolation must be strictly adhered to and it does not depend on whether the contact was in the workplace, abroad or in a night club.

Estonia has laid down a 14-day isolation requirement for people coming from countries at risk. As an alternative to isolation, several countries (Germany, Austria, Iceland) accept a PCR test on arrival, which Iceland requires to be repeated on day 7. The PCR test could also be combined with an antibody test, especially if a person is known to have had COVID-19. The retesting of PCR-positives is not recommended as it makes little sense.

Hygiene rules have already been explained at length, so washing hands, disinfecting, staying at home when ill, etc. should become a social norm.

COVID-19 in Estonia

Similarly to other northern European countries, the current level of infection in Estonia is low (3.8/100,000 in the last 14 days), but the virus has not disappeared. Cases have occurred throughout the summer. Most cases have been imported, but the outbreak in Tartu also shows a local spread of the virus. As in other European countries, predominantly young people are affected: it is a disease of parties and gatherings. In general, young people tend to spread the disease better than the old; on the other hand, it is more severe among the elderly. About 15% to 16% of patients are older than 50 (the main group putting pressure on the medical system). During the March/April outbreak, more than 50% of patients were older than 50. The Health Board has currently been able to monitor contacts, but this is very resource-intensive and probably unrealistic if the spread of the virus increases considerably.

It is now clear that SARS-CoV-2 is not a short-term phenomenon, but will be around for years, if not decades. So, we must take this into account in our future action. Can we close down schools, leave people confined to their homes and stop external communication for years or find ways to live with the virus?

Restrictions cannot be completely avoided, but they must always be proportionate, timely and balanced. Strict and very early restrictions have not demonstrated a long-term effect in any country (China is an exception). They may work at first, but once they are slightly relaxed, the virus will come back.

It is not possible to avoid all infections, but it is reasonable to keep infections at a level that does not overburden the medical system and impede the treatment of other diseases.

Estonia’s future strategy should seek to maintain as normal a life as possible and the implementation of restrictions should be focused and considered when the medical system starts to show signs of failure. Testing capacity is in place in Estonia and there should be also enough personal protective equipment, so the test-and-trace strategy seems to be the best option.

Each institution/sector should develop a long-term strategy for living with the coronavirus. For example, how to keep the entertainment sector working in such a way that people are entertained without putting their lives at risk. The same applies to nursing homes, which pose a very high risk in terms of coronavirus. It is very inhumane to close old people in homes for years without any face-to-face contact with their loved ones. Making all schools to implement full e‑learning for several years might not be sustainable. But it may work to some extent, especially in senior school stages. The current situation requires innovation and brainwork from all of us.

In the fight against coronavirus, we should not forget that there are many other diseases in the world and that restrictions also affect the occurrence of other diseases. For instance, closing down schools means that vaccinations done in schools are cancelled or at least delayed, potentially leading to outbreaks of other infectious diseases. The closure of kindergartens also disrupts the work of many other institutions, including the organisation of medical care. Soon it will be time for flu vaccinations and this should not be forgotten in the rush of dealing with coronavirus.

The situation requires understanding, patience and responsible behaviour from all, the young and the elderly alike.

Professor Lutsar published this article on social media on 3 August.