Irja Lutsar: Number of infected set to grow rather than fall

Irja Lutsar.
Irja Lutsar. Source: Siim Lõvi /ERR

Because the coronavirus is widespread in Estonia and Europe, the number of infected people will rather grow than start to fall in the near future. A noticeable drop in the number of infected people will only appear once inoculation has started, Irja Lutsar writes in her COVID-19 overview.

The coronavirus pandemic has raged for almost a year and for almost a year, I have been checking the Worldometer database every morning, as I'm sure millions of other people have.

Over 70 million cases of the virus have been diagnosed and COVID-19 has claimed over 1.5 million lives. That said, mortality rates differ greatly from one country to the next – from 0.3 per million in Tanzania to 1,532 per million in Belgium.

COVID-19 has behaved differently from most infectious diseases that usually ravage poorer regions. Looking at mortality in the world's poorest countries, we see that the rate per one million residents is 18 in Congo, five in Uganda, nine in Tajikistan, 20 in Haiti, 15 in Ethiopia, 199 in Kyrgyzstan and 18 in Uzbekistan. In the world's wealthiest countries, the figure is 809 in Luxembourg, 70 in Norway, 671 in Switzerland, 82 in Iceland, 85 in Qatar, 726 in Sweden, 158 in Denmark, 903 in USA and five in Singapore.

What has gone wrong in wealthy countries? More detailed analysis will occupy scientists for years to come, while relative importance of the elderly and a large part of them inhabiting nursing homes seems to be one of the main factors.

Lack of a vaccine and effective medicine that would have been another advantage for the wealthy part of the world is another factor. Many have asked what would happen were we to do nothing at all. Iran is a good example of this as the disease has been spreading there since February and the number of infected people has grown rather than fallen. Iran laid down new restrictions in late November and both the number of infected and deaths have started coming down in recent weeks.

We use historical measures to prevent COVID-19

Unfortunately, we currently only have non-pharmacological methods that I'm sure everyone is familiar with by now at our disposal (isolation, hand hygiene, face masks, maintaining social distance) that help slow down the spread of the disease but cannot eradicate it. Mankind did a poor job sticking to isolation rules 400 years ago and it still seems to be the case today.

What is more, these historical methods are not really compatible with democracy and personal freedoms and are met with defiance in modern individualistic societies. While lockdowns help suppress the virus, the previous situation starts to return as soon as measures are relaxed. Any tough measures opted for should be long-term.

Hong Kong and South Korea are seeing the third wave of the virus. We can also see the case rate going up again in the Netherlands where restrictions were relaxed only by very little. The UK has also returned to the same number of infected people it had when recent measures were laid down.

Spread of the virus

We have learned a lot more about how the virus spreads. It is a virus transmitted human-to-human that needs close contacts between people. While it has been suggested the virus could be carried by minks, cases transmitted this way have been marginal in number.

Even though it has been demonstrated the virus can survive on bank notes and surfaces in laboratory conditions, such transmission is also secondary. Therefore, avoiding contact with symptomatic and pre-symptomatic people (in other words, cutting down on all non-essential contact) could be the best way to avoid being infected.

Surveys have shown that the risk of infection is greatest for people sharing a household with a PCR-positive person as around 40 percent of those who fit that description are diagnosed. We can also see it in Estonia where catching the virus from family members is one of the main ways it spreads.

Risk of infection is smaller in communities where around 3-4 percent of those who have contact with infected persons eventually take ill. The latter largely depends on the duration and intensity of the contact. Risk of infection is considerable also in closed collectives, such as nursing homes, prisons etc. Students have been shown to be at risk from the disease in dormitories but not so much in class.

The considerable risk of transmission inside families has likely prompted strategies of combating the virus used in Asia where the majority of PCR-positive people were isolated in special coronavirus homes as opposed to their own dwellings.

In spring, when PCR residual positivity was not fully known yet, people spent over a month in such coronavirus homes. Western countries have not used such measures on a large scale. Therefore, if a member of your family is PCR positive, they need to keep their distance from others and wear a mask whenever possible.

Isolation and quarantine

It has also become clear that a PCR-positive person is infectious a few days before showing symptoms or days one through five after symptoms manifest. The risk of infection is considerably lower after that, while not nonexistent.

That is why a lot of countries have shortened quarantine periods from 14 days to 10 and some are considering further reductions. This could clear up some of the confusion arising from different quarantines.

Immunity and antibodies

We have learned that most patients develop antibodies after recovering from COVID-19 irrespective of the severity of the disease that newer studies have shown persist for at least six months (no longer-term data is available).

While cases of repeat infection have been described, they remain marginal in number.

That is why several countries no longer quarantine people who have recovered from COVID-19 or order them to self-isolate. At the same time, there seems to be no clear position on whether this only applies to those who have had the disease inside the past three to six months or everyone.

Missing antibodies might not equal missing immunity as a person's immunological memory could still offer protection. Relevant discussions have begun in Estonia but haven't produced decisions yet.

Vaccines and medicines

The first vaccines have come to market and the first people been inoculated. Regulators have authorized vaccines for use under extraordinary circumstances.

At the same time, vaccine studies are far from over and new data is constantly being collected, with inoculation recommendations revised as necessary. Both mRNA vaccines performed very well in clinic trials at preventing the COVID-19 disease – including severe cases – while that requires two doses.

The adenovirus receptor vaccine has also proved effective in trials. That said, we do not yet know whether the vaccines help prevent asymptomatic transmission of the SARS-CoV-2 virus and how long immunity lasts.

Therefore, vaccines are initially a good fit for those who sport a high risk of coming down with severe COVID-19, which is why during a time when there is not enough vaccine to go around, front line medical workers are being prioritized to ensure operation of hospitals, as well as staff and residents of nursing homes as the latter are most at risk from the disease and its more serious consequences.

Unlike vaccines used primarily on children and young adults, coronavirus vaccines are most important for older generations.

If the vaccine situation is good and there is light at the end of the tunnel, we have not seen a major breakthrough in terms of coronavirus medicines, while several trials of completely new and slightly older drugs are underway. Hope remains.

When will it end?

It is hard to believe a respiratory virus will disappear in winter, especially in the conditions of wet and relatively warm weather we've been having. Because the virus is widespread in Estonia and Europe, the number of infected will grow rather than fall.

A noticeable drop in the number of infected will likely only happen once vaccination starts. If herd immunity requires 75 percent of the population to be vaccinated (or to have antibodies), 40 percent will be enough to considerably cut the number of cases.

When that will be largely depends on how quickly vaccines come to market and on inoculation progress. Provided there will not be major setbacks, next fall should be easier in terms of the coronavirus.

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Editor: Marcus Turovski

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