**3.2 Vaccination projects**

In order to fight this pandemic, global vaccine development efforts have been accelerated. Clinical development consist of three phases. In Phase I, a small group of people receive the vaccine. In Phase II, the vaccine is delivered for people whose characteristics such as age and physical health are similar to which ones the new vaccine is intended. Finally, in Phase III, the vaccine is given to thousands of people and tested for efficacy and safety [23].

Approximately, there are 56 verified effective vaccines candidates for COVID-19, produced in China, North America, Europe and Australia [24]. Furthermore, thanks to new technologies, it is possible to develop different types of vaccines. In


#### **Table 5.**

*COVID-19 vaccine types.*

**Figure 5.** *Types of vaccines for COVID-19. Source: [23].*

**Table 5**, we present the vaccine types for COVID-19. Finally, in **Figure 5**, we present the most important vaccines types against COVID.

#### **3.3 The impact of vaccination**

In order to evaluate the impact of vaccination, we analyzed, how the number of total people vaccinated affects the number of confirmed cases and deaths. We took data from a data-set that store information about vaccinations [28] and other that daily store information about the number of confirmed cases and deaths around the world [29]. For instance, in **Figure 6**, we present the relation between the total number of people vaccinated and the total number of confirmed cases and deaths. In this plot, we evaluated US, India, France, Russia and Brazil. Moreover, we

*COVID-19 Pandemic: Analysis and Statistics of Confirmed Cases DOI: http://dx.doi.org/10.5772/intechopen.98891*

#### **Figure 6.**

*The effect of vaccination in total confirmed cases and deaths in US, India, France, Russia and Brazil. (a) Confirmed cases. (b) Deaths.*

#### **Figure 7.**

*The effect of vaccination in total confirmed cases and deaths in Argentina, Colombia, Peru, Chile and Mexico. (a) Confirmed cases. (b) Deaths.*

noticed the differences between some countries (US is the country with the major number of people vaccinated). Furthermore, we noticed how the number of confirmed cases and deaths were reduced since the vaccination started.

Latin American countries, present a similar behavior. In **Figure 7**, we plotted, how the number of people vaccinated, affect the number of confirmed cases and deaths. In this case, Chile and Mexico are the leaders of vaccination in Latin America. Moreover, the number of confirmed cases and death seems to decrease in this countries.

#### **4. Forecasting COVID-19 confirmed cases**

In this section, we evaluated the accuracy of some methods to predict the confirmed cases of COVID-19. In this case we choose Multiplicative Trend Exponential Smoothing (MTES) and Long Short-Term Memory (LSTM), as it was proposed in a previous work [7].

#### **4.1 Multiplicative trend exponential smoothing**

The MTES method [30] is usually known to predict non-seasonality data as modeling with a trend in a multiplicative way, differing from the Hold (additive trend) method that considered the trend in a additive way [31]. It's known that on the real world the majority series have multiplicative trends. The MTES method works with two smoothing parameters designing the local growth rate by smoothing successive divisions from the local level [32].

## **4.2 Long short-term memory**

LSTM is a recurrent neural network [33]. This network introduces the concepts of memory cells (**Figure 8**), this unit is composed of a cell, an input gate, an output gate and a forget gate. This cell remembers values over time intervals, then the other gates regulate the flow of information.

#### **Figure 8.**

*Architecture of memory cell cj and its gate units inj*, *outj. Source: [33].*

#### **Figure 9.**

*Prediciton of total and daily confirmed cases in United States, using LSTM. (a) Total confirmed cases. (b) Daily confirmed cases.*

#### **Figure 10.**

*Prediciton of total and daily confirmed cases in India, using LSTM. (a) Total confirmed cases. (b) Daily confirmed cases.*

*COVID-19 Pandemic: Analysis and Statistics of Confirmed Cases DOI: http://dx.doi.org/10.5772/intechopen.98891*
